John French
A Black Library writer. He's not C.S. Goto or Gav Thorpe, but he's got a big problem: he has zero understanding of why fans of a given faction like that faction. The worst offense is his treatment of the Iron Warriors, who he writes as complete retards who only win because they're lucky and have no self-control. Us Iron Warriors players like them because they're the most disciplined and pragmatic legion; the one that will do anything to win. John French doesn't realize that good characters have goals of their own. The Iron Warriors want to build their own empires after they're finished wrecking the Emprah's. But nobody told Johnny.
His Ahzek Ahriman book series is pretty good though, it's worth a read. Furthermore, he does a great job with the Imperial Fists, as The Crimson Fist and especially Praetorian of Dorn show. He completely nails their sense of duty and their stoicism, as well as their deep-seated fear that they aren't good enough.
To summarize, HE CANNOT BE ALLOWED TO WRITE IRON WARRIORS
In this he's kind of similar to ADB. Both are excellent writers but completely ruin certain factions. In John's case its the Iron Warriors in ADB's case its the Emperor.
A non-IWfag's opinion
While Autistic Iron Warrior Fans hate French, it's because he has a different opinion of them and Peturabo that fits another side to them. French paints them as a grim force that cares nothing for casualties, to the point where their Primarch would kill a tenth of his Legion just to teach it a lesson. Hos Peturabo is the Iron Tyrant, Space Stalin, all the bloodstained dictators of history but as a Primarch.
At Forgeworld
With the sad death of Alan Bligh, John French has taken over as the main fluff writer for Forgeworld's Horus Heresy Books. Expect butthurt Iron Warrior Fanboys when French writes the Battle of Tallarn book.