Editing Warhammer 40,000 8th edition (section)

===Core Rules===
*'''"Not AoS 40k"''': From what we've seen so far thanks to GW actually disclosing their design process via Warhammer Community, many of the overhauls to the 8th edition ruleset are (unsurprisingly) modeled on equivalent rules developed for [[Age of Sigmar]]. However there is also a ''lot'' of inspiration being drawn from older editions of 40k, to the point that some of the "new" mechanics are recognizable from as far back as 2nd edition. Despite what the doomsayers will tell you 8th is ''not'' just Sigmar with guns -- they're trying to take what good things AoS had and overhaul the 40k we all love with that.
*'''<s>More</s> <s>Less</s> Differently Random''': Deployment-phase rolls that decide what your units can actually do for the rest of the game seem to be gone (and good riddance!), also gone is the random scatter for blasts and deep-strikes or random outflanking, but instead many weapons now deal random number of shots/hits or random damage in order to compensate for the absence of templates (see below) and woundbloat on the vehicles and monsters, and charges are still random range despite literally everyone wanting them to go back to fixed, meaning the result of every action may be even less reliable. This could be good or bad, depending on your tastes.
*'''No Templates:''' Templates are gone, Just like Squats. Weapons like Flamers (except the ork burnas) will simply fire d6 automatic hits just like the spread weapons in Age of Sigmar (they don't ignore cover any more, though). Blast weapons like the Leman Russ work similarly by firing a random number of shots, though they do not hit automatically.
**This change is [[skub|skubtastic]]. Those in favor of the change say it speeds the game up, because scatters took too much time to resolve, and "blasts only hit 1 or 2 models anyway because people always spread out for max coherency." Those against it argue that this change leads to rule abuse or violations of common sense, such as Guard Conscripts forming up in musket lines ([https://1d4chan.org/wiki/Mordian_Iron_Guard as thematic as it might be for some guard regiments]). More controversially, the changes to Flamers mean certain ones (Example: Inferno Cannons) are arguably better at [[what|anti-aircraft]] than [[derp|crowd control]]. However, since then some weapons have gotten an equivalent via bonuses to hit units with a certain number of models, or inflicting wounds to multiple units within a given distance of the original target.
*'''<s>Far Fewer</s> <s>More</s> Reworked Special Rules:''' Uncapping and standardizing stats, and adding the movement stat all by itself, will eliminate a lot of "hacky" old special rules. On the other hand, special rules are now unique to the army or unit. Based on the faction focus material we've seen so far, 40k will be seeing a lot of "unique" special rules that are basically the same rule with different names and slightly different wording, much like in 3rd edition.
**To give you an idea of how this will work, [[Nurgling|Nurglings]] will have a special rule unique to Nurgle called "Disgustingly Resilient" that lets them ignore wounds on a roll of 5 or 6, instead of having the (now nonexistent) Feel No Pain special rule normally found in the core rulebook. Ork, Tyranid, and Blood Angel units that would have had FnP will have ''the exact same rule text as Disgustingly Resilient,'' just with a different [[meme|ASSFAGGOTS-like ability name]] and occasionally a different roll requirement. Same with other common rules like Hatred, Overheat, and Deep Strike. This means that any attempts to write rules that interact with these common, basic mechanics will be ''even hackier'' than 7th edition's special rules because they can't just refer to a common special rule by name anymore.
*'''Bookkeeping Reduction''': The amount of one-use gear or rules was reduced quite drastically, and with the removal of random warlord traits and psychic powers there is no need to keep track of those (as they're already written in the army roster). On the up side it speeds up the game and removes the need to use lots of tokens or notes, but the trade-off is that there is one more layer of tactical decision making shaved off the game - timing things like combi-weapon use or Waaaaagh! activation used to make or break games, and now it's gone. 
*'''Datasheet Overhaul:''' With the intent of eliminating the need to carry around half a library's worth of books, a unit's datasheet will contain almost all the information it needs to function, including rules for weapons and abilities. With a few exceptions. Units with a ''ton'' of options, like Tactical Squads, will only have the stats for the most common choices in their datasheet, with the rest of their choices getting rules elsewhere. Explanation of common or army-wide special rules may also be left out. So the special rules and wargear lists aren't completely disappearing from the rulebooks and codices, but active reliance on them will be greatly reduced.
*'''Independent Character Overhaul:''' Characters can no longer join units, or join together with other characters to form a super-unit. In GW's own words, ''"The age of the prefix-star is over"''. Instead, ICs will have effects that cover all units with a certain keyword within a certain radius. Also, ICs with less than 10 wounds [[Plot armor|cannot be targeted in the shooting phase]] unless they're the closest enemy model (except by units with sniper and similar rules), so there's less worry now about losing your special snowflake to a railgun. Lastly, ICs have a rule called Heroic Intervention that lets them pile in and attack charging enemies even if they themselves aren't charged.
**On the other hand, it is possible (even with Command rerolls) for a squad to make it into combat, but an Independent Character to fail a charge roll, leading to situations like Khorne Berzerkers making it into melee while Kharn takes a smoke break. You can only shoot a Character if it is the closest model, even if said character is standing in the open and the only closer unit is a Rhino locked in combat (which you obviously can't shoot either).
*'''Summoning Overhaul:''' No more [[The Ultimate Chaos Daemons Cheese List|infinite Daemons]] in Matched Play. If you want to summon units, you now need points set aside to spend on them in advance, and summoning itself is going to be separated as its own form of deployment, alongside deep striking or outflanking. (Basically Summoning is a special form of reserves where you don't have to choose what's in reserve until you actually summon it, letting you change your list mid-game). Think of it like Schrodinger box, The cat is either dead, alive or secretly a baneblade and you and your opponent don't know until the wave form's collapsed and the box is opened (or unit summoned in this case).
*'''Points and Power Levels:''' Units now have power levels (anyone who makes the [[Meme|obvious joke]] gets a mini down the windpipe) to approximate their average effectiveness, and are meant as a fast and casual balancing method for Open and Narrative Play. This system is similar to that of 40k competitor [[Warmachine]]. Not to worry, though, the points system we all know and love is still around in Matched Play if you want to use it, and is just as detailed as before (though likely with the usual tweaking of points values that comes with every new edition). In a bit of an odd move, though, points are ''not'' in the datasheets for units anymore, instead being detailed elsewhere in the rulebooks. Part of the reasoning behind this is so 40k can use the same "Living Rulebook" approach used in Age of Sigmar by way of releasing updates to address balance issues without forcing anyone to buy an entirely new Codex to do so. Might be a little obtuse, but on the other hand this means nobody has to worry about being saddled with an [[Chaos Space Marines|outdated]] [[Orks|Codex]] [[Tyranids|again]], so the long reviled "Codex Creep" might finally be over. 
**Power Levels appear to be average points for the unit/20, rounded - so e.g. a Captain in Gravis Armor is 148 points or Power 7, while an Inceptor squad is 159 points or Power 8.
**Points are amended in Matched play via Chapter Approved and other updates, but Power Level is not. Since more of the point changes are reductions in price, the overall P2P ratio is changed (around 19.5:1, but individual army ratios may be different).
*'''Casualty Overhaul:''' When a unit loses models, instead of plucking whatever guys are closest to the attacker, the controlling player gets to decide which ones are removed.
**This means you will almost assuredly get far more mileage out of your special weapons, and tactics like hidden power fist are viable once again.
**Additionally, this probably means that musical-wounds shenanigans like the Nob Bikerz of yore are gone.
**On the downside flanking enemy units to kill weapon specialists without the need to chew through the meatshields in the front is no longer a viable tactic, taking a lot of depth out of close-range firefight tactics.
**This also presents the possibility to score more hits than there are models in the unit, making flamers and explosives a much greater threat to small units that rely on having multiple wounds to stay around. On the other hand, they are a much lesser threat against large units, as you cannot use clever positioning to guarantee you land more hits - your shot volume is random and not manipulatable through skill.
**Flamers and most template weapons have lost Ignores Cover, although the ability still exists (and is not referred to as such, under the new policy of avoiding naming rules whenever possible, and if you must name it, giving the same rule a different name every time you use it).
**Different template weapons do have different ranges now, which is nice.
*'''No positioning mechanics''': With no vehicle armour facing, the absence of templates, and manual wound allocation, there is little to no benefit from shooting enemy units from their flanks or rear. Army-specific rules seem to lose any semblance of positioning rules as well, seeing as Knights get their ion shield changed from 4++ from one facing to 5++ all around. This would speed up the game a bit, but at the cost of altering an entire tactical layer of it. Expect deep strikes, outflankers and hyper-mobile units to be used very differently than they are now.
*'''No more Fire Arcs''': All vehicles and fortifications measure LOS from their hull. Another [[skub]], this means a Valkyrie can shoot all of its weapons if it can draw a line to something with the tip of its wing.
*'''Twin-Linked Buff''': Twin-linked weapons no longer reroll to-hit dice; instead, they now ''double'' the number of shots they would normally fire. This makes the vanilla Land Raider go from schizophrenic to dangerous and makes a lot of Ork vehicles downright terrifying though unless they also get an accuracy buff Orkz will notice the difference least since they got the biggest benefit from old twin linked. Land Raider Crusaders are going to become the anal rapists of the battlefield; assuming they stay the same it will be like a metal box with a tactical marine squad glued on to each side! Expect some buzz from Tyranid dakkafexes and spinegaunts, as well. If you thought playing against tau broadside spam was disgusting before, you ain't seen nothing yet.
*'''Combi-Weapons Buff''': Combi-weapons are no longer one use for the specialist weapon; instead, they can fire as either the normal or specialist weapon, or even fire both at the same time (but with a -1 to hit). They are now effectively a flat upgrade compared to either a basic weapon or their specialist weapon equivalent, since they can switch between either role with impunity. However, expect there to be ''some'' manner of trade-off, most likely a points increase if the Sisters of Battle leak is legit (claims to charge ''19'' points for a combi-melta). Otherwise units like Sternguard are going to end up ridiculously overpowered, and there won't be any reason at all to take regular special weapons over a combi-weapon.
*'''Characteristic Overhaul:''' No more rules for high BS/WS, those stats are expressed as to-hit rolls now so nobody can have a better hit chance than a 2+ without special rules. Also, other stats are no longer capped, so you can have Strength, Toughness or Wound values higher than 10.
**'''No more D Weapons:''' With Strength stats no longer capped at 10, weapons that previously needed the Destroyer special rule to kill everything will now likely just have really high strength and/or cause a lot of wounds. For example, the Knights' Reaper Chainsword now deals 6 damage- more than enough to wreck infantry and leave even heavy vehicles hurting.
*'''Save Modifiers:''' Gone are the AP values of weaponry, and now we're getting back a mechanic not seen since 2nd Edition 40k, or more recently Warhammer Fantasy before it got squatted. The save modifier alters the target number needed for an armor save to work (e.g. with a -2 modifier, a unit which would normally have a 2+ save would now act as if they had a 4+ save instead). This is going to be a nerf to AP5 weapons like Bolters and flamers, which can now be stopped by Ork and Gaunt armour and will hit 5+ armour 66% as hard as before, the same with AP4 against 4+ and AP3 against 3+. In exchange, any armour piercing weapon will be much more effective against heavier armour, with heavy bolters able to better threaten tanks and MEQ/TEQ in the open, and hot-shot lasguns being better against TEQ than MEQ. Terminators will be more fragile in general unless they change how Invuln saves work. In essence, there will be far fewer hard counters and all weapons will be more versatile in general, eliminating some of the need to carefully choose weapons and targets. Dumbing down the game? Sure. Balancing the game? Probably.
*'''Movement Phase Overhaul:''' The movement stat is back, and Running has been rolled into the Movement phase by being able to roll to add a little extra distance at the expense of shooting and charging. Some Flyers will have a minimum movement distance in addition to a maximum movement distance; if they are unable to move the minimum distance or if this distance would force them off the battlefield, they are destroyed.
**Movement-based rules like Slow and Purposeful and Fleet are probably on their way out, as fast and slow units won't need special rules to represent that anymore. 
**Deep Striking equivalents set up at the end of the Movement Phase; while they cannot move or advance further and count as having moved for that turn, they can still shoot or charge normally. 
*'''Psychic Phase Overhaul:''' Rather than each of your psykers contributing to an Army-wide dice pool like in 7th, each psyker will once again have the capability to reliably cast their own powers. Any psyker model will be allowed to cast as many powers as their individual entry states, and instead of harnessing Warp Charges on a 4+ or making a Leadership check, the controlling player rolls 2d6. If the value surpasses the amount required to cast the power, they succeed, and any enemy psyker within 24" will have the option to Deny it. Of course, models can only Deny The Witch once per turn for each Mastery Level they have.
**Stronger powers will have a higher Warp Charge value, and will therefore be harder to cast.
**Every faction with psykers will have its own unique psychic powers, and all psykers know Smite by default, which has a Warp Charge value of 5 and now causes D3 ''mortal'' wounds to <s>a target</s> the closest target within 18" (a marked difference from the AoS Arcane Bolt), or D6 mortal wounds if you roll 10 or above on the psychic test. That being said, cheaper psykers like the Rubric Marines' Aspiring Sorcerer or grey Knights have a weakened version of it that causes fewer wounds. Generic core rulebook disciplines like Biomancy and Daemonology are gone.
**Perils of the Warp now occurs on double 1s and double 6s during psychic tests. It causes D3 mortal wounds to the psyker, and if it dies as a result the power being manifested doesn't go off and all units within 6" of the psyker take d6 mortal wounds.
**You can pick the Psychic Powers you want now, rather than rolling for them and hoping you get the right number.
**In matched play, Psychic Focus means you cannot cast the same power more than once per turn unless that power is Smite. Expect Psyker armies to be about spamming the most cost-effective smite.
*'''Shooting Phase Overhaul:''' In addition to being unable to shoot after Advancing or Falling Back, models can't shoot if there's an enemy model 1" or less away from them, which combines with the new assault rules to make close combat more dangerous. Heavy weapons no longer snap-fire if firing on the move, and instead get a flat -1 to hit modifier if fired on the move (which applies to vehicles too). Cover saves now add a bonus to the armor save instead of acting as a blanket save, and in certain cases only applies to specific unit types (e.g. Infantry can benefit from a crater's cover bonus, but a vehicle can't).
**Split Fire for everybody! All squads can now use different weapons against different targets. No more situations when your bolter marines have to hose down a Land Raider with ineffectual shots just so the one dude with a melta needs to take a shot at it. This goes down to individual models - your crisis suit can shoot missile pods at that pesky vehicle while flaming some nearby infantry.
**Every model can fire all their guns (with some exceptions).
***Only one model per squad can use a grenade at a time (and they can't fire anything else).
***Everyone else has to choose between firing all their pistols and all their non-pistol, non-grenade weapons.
**Pistols are exempt from the restriction against shooting when an enemy is too close, and in fact a pistol user can fire at the closest enemy target to them even if they're locked in combat. This is a massive game changer to dual-pistol wielders such as Cypher, and also gives units like Assault Marines a little extra boost when they're closing in on an opponent. It might also make Plasma Pistols worth taking after all these years.
**The alteration in how cover saves works means that some weapons may be able to reduce the save to the point where the cover bonus is canceled out, so don't be tempted to think you have a chance to survive a lascannon shot just because you're hiding behind a piece of rubble. Weapons that currently ignore cover will not be affected by the cover bonus at all. This may have the effect of making [[Imperial Guard|the units that need cover saves the most]] the least able to take advantage. However between these changes and the ones to how AP works, heavy infantry become the ones who rely on and benefit from cover most, with 2+ and 3+ armour being more vulnerable to getting caught in the open by heavy bolters than lighter infantry are, while light infantry will be able to stand up to fire from bolters in the open but plasma guns will be able to blast anything in cover better than flamers can.
**Assault weapons can be fired after advancing, but take a -1 penalty to hit for doing so. This makes weapons like flamers, meltas, and the like much nastier than they used to be. 
**Plasma weapons have reverted to the 2nd edition style of having two firing modes: one that's weaker but safe to use (although in this case it's still S7 AP-3), and one which hits harder and deals more damage but runs the risk of killing the user (no armour saves allowed for that version of gets hot, and instead of removing a wound it kills the model outright). It turns out that if you give an archmagos ten millennia he actually ''can'' figure out how plasma works.
***Fluff vets can [[Rage]] at the fact that apparently Chaos Space Marines use similar rules...despite old fluff or old crunch for them. (Back in 2nd, Gets Hot was a specific rule for CSM, but their plasma weapons had better rate of fire).
***The Primaris Marines' Incinerator has -4 AP and +6" in range over the regular plasma gun.
***Do note that when overcharging, a to hit roll of 1 kills the user without any saves possible, '''even if they're a character! EVEN IF THEY ARE A VEHICLE!!!''' Watch the fuck out if you're thinking about supercharging any Captain's/Chapter Master's/Razorback's guns as there is going to be a 1/6 chance they die from it.
****Note that due to the FAQ explaining that roll modifiers apply when determining if you roll a 1 or 6, [[Awesome|this means that any ability that grants +1 to hit makes you immune to rolling 1s]]. On the other hand, the reverse is true, meaning Overcharging is [[what|more likely to kill you at nighttime]] (Well you can't see the power gauge can you?).
****Leman Russ Tanks have a special rule that means instead of being instantly killed, they lose 6 wounds (half their max) and the plasma weapon is destroyed and unusable for the rest of the battle.
*'''Assault Phase Overhaul:''' Initiative is gone. Whoever charges first attacks first like in Age of Sigmar. This actually gives assault based armies a chance now ([[Orks]], [[Dark Eldar]], [[Tyranids]], [[Blood Angels]], Thunderwolf spam, Khorne armies). After chargers, players alternate "activating" units to fight, a la [[Heroclix]]. Challenges are gone. You also no longer gain extra attacks for multiple close-combat weapons or charging (unless the unit has an appropriate ability).
**[[Daemonette|Daemonettes]] and Eldar CC units, among other high-I units, have a special rule that lets them almost always strike first even if they don't get the charge, unless both units have the same kind of rule in which case it depends on whose turn it is. (Note the similarity to [[Warhammer Fantasy Battles|Always Strikes First.]])
**Units now have the ability to fall back and walk out of engaged combat in the Movement Phase (it's basically the old 5th Edition Space Marine Combat Tactics, but for ''everyone''!), BUT, they sacrifice the ability to advance or charge in that turn (and shoot, unless the unit in question has the right keyword). This gives Guard armies a chance now. However, falling back doesn't work if you're surrounded so it's not foolproof. 
**The first profiles indicate that WS4 is a 3+ to hit in CC, which makes melee combat quite a bit more aggressive. 
***In fact, WS1..5 seems to be 6+..2+ now, followed by a lack of scaling - both a Space Marine Captain and Guilliman now hit on a 2+ in melee. Expect anything with WS6+ to be reworked some other way to improve its melee capabilities, such as additional A or S, or improving its melee weapon(s) instead (Space Marine Captains seem to get +1A for their WS6, but we don't know enough right now to say much more).
**Consolidation during activation allows a 3" move, which may bring you into combat with a new enemy, if you choose.
*'''Melee Weapons Rebalancing:''' The melee and power weapons were redone now that they all use differing AP values and Unwieldy no longer exists. Power Swords now have more penetration than axes (which should have been the case in the first place since they have a longer blade) but provide no strength bonuses. Power Mauls are about the same, more Strength for less AP, and Power Fists now only have -1 to hit and cause multiple Wounds at Sx2, AP-3 (that's right, Power Armour now helps against Power Fists). Melee weapons which once just acted like basic CCWs (e.g. chainswords and choppas) now grant one extra attack. 
*'''Morale Overhaul:''' Leadership rules are changing; it's almost the same as Age of Sigmar's Battleshock: Roll 1d6, add up the amount of models lost and compare it to your Leadership value. If the result is greater, you remove the difference in models.
**Commissars negate this effect to an extent by limiting morale-related losses to 1 model per unit. This is a revamp of their "Summary Execution" rule, and your opponent can never choose which model gets the blam. 
*'''Reserves Overhaul''': While USRs like Deep Strike and Outflank no longer exist, unit- and faction-specific rules will serve a functionally identical role, albeit one tailored to said unit or faction (e.g. when a Trygon deploys by emerging from underground, another unit of Tyranids in the Troops slot can deploy with it to represent them using the Trygon's tunnel.) 
**Additionally, Matched Play adds the "Tactical Reserves" restriction- at least half of all units in a detachment must be set up on the battlefield, and any units that have not been deployed on the battlefield by the end of the third turn count as having been destroyed. In other words, no you can't just teleport your whole army of Deathwing Terminators in at once. 
*'''Keyword Abilities and Allies:''' While allies are still available, keyword abilities will only affect specific models. On the one hand, this means that hyper-synergistic superfriends cheese is gone. On the other hand, this means that half your army is effectively on a separate plane from the other half if you're using allies, and never the two shall meet.
*'''Play Mode Overhaul:''' As mentioned above, the General's Handbook's 3 Ways to Play is coming to 40k. Open Play will replace Unbound, and is even ''more'' freeform than Age of Sigmar: the rules text amounts to "just grab some [[Games Workshop|'''official Citadel Miniatures''']] and do whatever the fuck you feel like." For Narrative and Matched Play, armies ''must'' be battle-forged, so no more overlap between battle-forged and unbound.
*'''Detachment Overhaul:''' Decurions and Formations are gone. In their place, the classic Force Organization Chart is making a return, except there will be over a dozen different detachments to choose from that everybody can use, including the classic combined arms detachment, and as codices start to come out each army will get their own special versions as well (presumably bringing back Decurions/Formations as soon as an editor is asleep at the switch). These new detachments grant Command Points (see below), with detachments that require more unit choices yielding more Command Points.
**Flyers are now a distinct unit type for the purposes of Battlefield Roles, so they no longer compete with other unit types in their old slots. 
**Contrary to 7th Edition's efforts to turn all Dedicated Transports into Fast Attack choices and eliminate the slot as a whole, DTs have been maintained as their own category in 8th, and (based on the currently released examples at least) one Dedicated Transport choice can now be included for each other choice. Is this opening the way for shenanigans like guardsmen squads able to take [[Taurox|Taurox Primes]] as DTs? [[troll|We can certainly hope so]]. Er no, only Scions and Commissars can hitch a lift on a Prime sadly, but this doesn't prevent you from taking the unit as a dedicated transport; they will simply be unable to ferry units around the board.
**It's possible to take a unit with less than its minimum number of models, but you still need to pay for it as if it was at its normal minimum size.
***Aside from the new morale system emphasizing 1-model units like never before, transports can now carry as many squads as you like, providing a potential reason to take a unit with models you paid for but did not field.
*'''Wounds Overhaul:''' Everything is getting more wounds, with some units having twice as much as they used to, but at the same time more powerful weapons like Lascannons can dish out multiple wounds with each hit.
**The need to keep track of the double-digit wounds that the bigger stuff will have will likely see a spike in the sales of pocket notepads.
**On the other hand, players can continue to track them with dice, like before when things used to have 6 wounds at max; just use bigger dice, e.g. D20s.
**With the addition of the new Damage stat, some weapons - as stated previously - will have the potential to strip multiple wounds from single models, while flamers and the like will deal multiple single-wound hits for anti-horde while also gaining some utility for lightly armored units with low unit counts.
***Overkill damage doesn't spill onto other models, so dealing 6 damage with a lascannon to a Tac Squad won't cause 5 marines to die of shock at what happened to their buddy who took the hit. As a result, expect the meta to favor weapons with a reasonable number of attacks and medium damage, since overkill is now a waste in most situations.
**Every weapon in the game will have the potential to deal (at least a little bit of) damage to anything they hit, though playing weapons to their strengths will kill stuff far more efficiently.
**Rolling To Wound is still based on the target's toughness, but is greatly simplified. Instead of an entire 10x10 chart, To Wound is now determined with a simple table based on whether strength is twice (2+), greater (3+), equal (4+), less (5+), or half (6+) than the target's toughness. That's... actually a hell of a lot better. There's some debate on whether this is actually simpler or better, with Bolter and Lasguns now wounding T5 at the same roll, and Pulse weapons and Heavy Bolters treating Orks and Cultists as exactly as tough, though perhaps new rules and unrevealed details will avoid those shenanigans.
***As you may have already guessed, Instant Death is gone. Not that a character can't die to a multi-damage hit, but no more will your T3 HQ pop to some jerk with a lucky missile shot on turn 1.
***Mortal Wounds are now a thing, sitting somewhere between rending, instant death, and D damage. Mortal Wounds bypass to wound rolls, automatically doing one wound with no saves of any kind allowed (although secondary saves that replace the old Feel No Pain still apply). Another difference is that overkill wounds resulting from mortal wounds are the only kind that spill onto other models.
*'''Vehicle Overhaul:''' Hull points and AV are gone, and vehicles now use the same profile system as everyone else, bringing them more in line with the likes of Monstrous Creatures. Yes, bolters and lasguns ''can'' hurt Land Raiders and Knights in theory, but when those vehicles have literally dozens of wounds on top of high toughness and saves (by GW's inaccurate estimates, it would take about 539.7 Marine bolters or 648 guard lasguns to bring down something like a Gorkanaut), you might as well leave it alone.
**Number of bolter rounds to take down a Morkanaut: '''486''' hitting on 3+, wounding on 6+, being saved on 3+, to take down a model with 18 wounds. Lasguns require the ''same'' number of ''hits'', as bolters and lasguns are now both AP-, and the difference in Strength between them only matters against models of Toughness below 8, but the guard tends to hit on 4+, so they need 648 rounds. The new rules broadly favor Attacks over AP over Strength, as shown below, with D being as good as Attacks ''provided your target has enough wounds to take the damage''.
**Eldar only require 194 Shuriken Catapult shots to down a Gorkanaut, due to Bladestorm. This number can be reduced further with judicious use of Doom. 
***Number of Space Marine-wielded and Guard-wielded Lascannon shots for comparison: 13.89 (13 31/35) and 18.51 (18 18/35), respectively. This is primarily due to Lascannons dealing 3.5 damage per shot, but also significantly due to vehicles having an armor save now and Lascannons having AP-3.
***Again with a Heavy Bolter: 54 and 72 shooters, after accounting for 3 shots per gun.
****Now that models with two Heavy Bolters shoot both of them, rather than Twin-Linking, that's obviously 27 and 36 for any of those, such as Inceptors or Centurions.
***Hellblasters will take 81 shots (so 40.5 shooters at range 15") non-overcharged, or 27 (13.5) while overcharged, killing, on average, 4.5 (9) shooters.
***Leman Russ Battle Cannons (so hitting on 4+): 15.43, 11.57 with hitting on 3+ (that's number of guns firing, accounting for both random A and random D). That's just an average, of course; it can take you anywhere from 6 to 108 shots (each of those cases are odds 1/18, though).
***Meltaguns at half range: 12.07, 16.10 (melta now adds an unkept die to the damage roll at half range, regardless of target). Note how they take ''more'' shots than the Battle Cannon needs, on average; this is due to the Battle Cannon's much higher (average) A vs the meltagun's higher average D and higher AP.
**Vehicles can now charge and engage in melee, replacing Tank Shock. While they tend to have high Strength and decent Attacks, many of them have terrible WS (with the exception of close-combat dedicated walkers like Dreadnoughts or vehicles with attachments that make them very nasty when ramming, like the Goliath Rockgrinder). This means it is often laughably easy to use cheap infantry to tarpit vehicles which do not Fly or have a similar rule (typically due to being very large and on legs), or, even funnier, tarpitting a non-Flyer with a Flyer. 
***While most fliers have the Airborne rule, preventing them from charging or being charged by non-Fly models, Valkyries have the Hoverjet rule which lets them ignore it for a turn. One player lost a game due to his opponent charging his Russ with a Valkyrie, and not being able to withdraw because the Russ was already backed up into a corner. 
**Vehicles have lost Relentless, and only some of them have gotten it back via special rules, so a substantial number of them are significantly less accurate than they used to be on the move. This is actually not Vehicle-specific; many other models have lost Relentless as well, including Bikes and models in Terminator armour. Combined with their newfound ability to get stuck in melee, this effectively means a double-nerf to Vehicles, helping significantly to contribute to 8th edition's apparent focus on infantry swarms, since your infantry now has fewer downsides compared to vehicles.
**Instead of rolling on the Vehicle Damage chart, the more damage they take, the lower your vehicles' (and Monstrous Creatures') stats will become, with different models suffering differing stat penalties - so far every model seen has suffered penalties to movement, but we have seen penalties to WS, S, BS, and A - but always, so far, suffering penalties to three different stats. As a result, the vehicle repair abilities of units like Tech-priests and Tech-marines will likely become much more important now since they'll be able to restore a vehicle to its full effectiveness.
**Vehicles now have armor saves on top of their high toughness and lack of facings, making some vehicles quite a bit more durable.
**The Super Heavy classification was changed to "Titanic" with as of yet unknown attributes. Super Heavy Walkers can just step over infantry models thanks to "Titanic Feet".
*'''Transport Overhaul:''' Units now disembark from Transports at the start of the Movement phase before the Transport itself moves, and any such units can move, shoot, and fight without any restrictions. It also appears that open-topped transports will allow the units inside to shoot out of them at any time and allows them to fire pistols if the transport is caught in melee combat. However, if a transport is destroyed any units inside it will die on a roll of 1. 
**Multiple units can all ride in one transport as long as it can hold all their models.
*'''Increased Customization:''' When Games Workshop teased the datasheets they showed that Space Marine, Chaos Space Marine, Tau, and, more interestingly, Tyranid units had <Chapter>, <Legion>, <Sept>, and <Hive Fleet> listed in their keywords, respectively; the Codexes for each of these factions add special rules for each of these keywords, replacing things like Chapter Tactics. 
*'''Command Points and Stratagems:''' All battle forged armies get at least 3 command points now, plus extra from certain characters or from taking specific detachment types. Command Points can be used to trigger Stratagems, which have a variety of useful effects such as gaining a single re-roll (1CP), auto passing a morale check (2CP), or getting one of your units to fight immediately after a charging enemy unit has fought (2CP). Additional Stratagems are available in alternate scenarios like Stronghold Assault, as well as in the different play styles, with Narrative allowing for six additional Stratagems based on the mission (3 for attackers and 3 for defenders). Maelstrom of War also has a Stratagem that allows a discard and re-draw of a Tactical Objective after generation (2CP).
**Each faction will also get their own unique Stratagems.