I think Ward is one of the most uneven writers GW ever had. He had some good moments, like with the Necron revamp, his writing for the elves in WFB, and that tweet where he roasted PETA, but then he also gave us 5th edition Ultramarines, Kaldor Draigo, the Khornate Knights incident, and that WFB Daemons of Chaos book that was so overpowered it broke the game and they had to release a new edition to fix it.
Obviously we can't know how much of that was him and how much was GW mandating that the new codex needed to be good to sell units, but it seems to me like Ward needed someone around to slap him when he started getting too enthusiastic about whatever he was writing and that never happened, so he just let his fanboyishness run away with him.