Phil Kelly
Not Matt Ward, so its all good.
Loves the space elfs.
Is writing the Black Templar 5th Edition book, so they won't have that pro-ultramarine racism shoved down their throats.
Praise the God-Emporer that his faithful servant Phil Kelly is making Black Templar spess mahinees and not Matt Ward, who ass fucked everything but the Ultramarines and Blood Angels, AKA FLYING DREADNOUGHT LIBRARIAN GUYS.
Ahem...
Out of all the current crop of Codex writers in 40k, Kelly is the one /tg/ doesn't have a beef with. This treadhead buffed the Imperial Guard into the stratosphere and is generally regarded to have fucked up the Tyranid 'dex, and, well, if you've spent any time here at all you know our feelings on a certain chapter's spiritual liege.
But Kelly's a pretty cool guy. He makes up fun, interesting mechanics, and turns out fun armies. He redid the Dark Eldar and made the Space Wolves a good choice, so hey. Fun guy.
Why Phil Kelly Isn't Matt Ward
Matt Ward designs armies by taking a bunch of units and cranking up their power level to MAXIMUM, either by making them extremely difficult to kill, extremely shooty, extremely choppy, or any combination of the three. He then assigns points values to these units based on what he thinks they should cost and peppers a few special rules here and there for "flavour" before shitting the Codex into the printers office, then returning home to wrap a picture of Marneus Calgar around his cock and masturbate furiously to Sisters guro pictures.
Phil Kelly designs armies that work as armies, rather than a bunch of units that rely on simply being "better" than anything the opponent can field in order to function proeprly. That's why neither the Dark Eldar or Space Wolves Codexes have big, fat, expensive units with Thunder Hammers, Storm Shields and Feel No Pain for 200pts - you can have units like this if you want them, but where Matt Ward has to give them to you for peanuts because he can't design an army without making it broken, Phil Kelly makes you pay through the bumhole for them because in his army books, these units are a luxury, not a necessity.
tl;dr: Phil Kelly is the best designer GW have got, the only one who makes armies that require any thought to play, and the only thing standing between the gaming side of 40k and complete assmongery. If your army hasn't had a new Codex yet pray to THE EMPRAH that it's Phil Kelly who is going to write the update because if it is, you can count on your book still kicking ass three years down the line, looking like a joke but being almost unbeatable in the right hands, or surviving through an Edition as a force to be reckoned with. Unlike certain army books written by a certain spiritual liege, which seem broken at first but quickly fizzle out as they collapse under the weight of their own hollow bullshit.
And listen to this charming motherfucker chat about the Deldar with the also awesome Jes Goodwin.