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. The Alpha Legion's contingencies and adaptability are also written believably instead of overdoing their mysteriousness. Ultimately, he portrays the bleak, "black and gray" morality that defines 40k while exploring elements of 40k frequently glossed over. 9/10 times, he writes an interesting story that focuses on right and wrong over smashing skulls, with very thought-provoking twists at times.
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.
While Iron Warrior Fans hate French, it's because he has a different opinion of them and Perturabo that fits another side to them, but backs it up with shitty logic and a very obvious bias against the IW. 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. His Peturabo is the Iron Tyrant, Space Stalin, all the bloodstained dictators of history but as a Primarch. Some non-IW fans argue that this interpretation is equally valid, or even Perturabo's "true" personality, but there's a clear line between being brutal and merciless in order to win and pissing away valuable resources to prove a point that's already been proven.
In Extermination, French writes that Perturabo decimated his Legion to make them willing to accept any number of casualties in order to win, after the Legion had just crippled itself as a military force because it was willing to accept any casualties. You read that right. He literally wasted a tenth of his available manpower to get the Iron Warriors to do the exact damn thing they were already doing. Their whole shtick may be not giving a shit about casualties, but French writes them as pointlessly wasting lives where other writers who have a better grasp of the Iron Warriors show them being evil and grimdark, but calculating and efficient rather than "Chenkov, but with Astartes instead of Guardsmen".
Has an often overlooked knack for portraying the more surreal and ephemeral aspects of Chaos as a force and faction, as demonstrated in the phenomenal Slaves to Darkness. He also showcased a bit of this talent when brought on to write Solar War, the first book of the Siege of Terra (though the full product was overall somewhat middling, some legitimately fantastic prose sprinkled throughout aside).
He's also part of the (large) writing team of Warhammer 40K: Darktide.
At Forgeworld[edit]
With the sad death of Alan Bligh, John French has taken over as the main fluff writer for Forgeworld's Horus Heresy Books, and it fucking shows. Suffice to say he is a talented writer who's not suited for that sort of thing at all, and the threads that focus on the lore were not kind. For those curious, either French or another writer had a serious hard-on for the Dark Angels, as an example, apparently 12 Cenobites in the lore were able to kill 50 of Horus' Justaerin Terminators, while only losing a handful of their own. They then went on to butcher the most skilled fighters the Sons of Horus had to offer during that siege, and after carving their way through every fucking opponent, were finally killed when the Destroyer Corps used Phosphex to finish them off. Lest you think the Dark Angels had lost though, the book makes it clear that the Sons of Horus got their ass kicked in every aspect of the conflict as well, despite having the element of surprise, careful planning, and a much greater force.
In case you were wondering, no, this does not translate well to the tabletop and the Cenobites are heavily outclassed by the Justaerin there, the best they can hope for is a mutual kill.