He was responsible initially at Marvel for bringing a large amount of order and reliablility to the comic books (many fewer Deadly Dateline Dooms - fillin issues). As with all these things though he started to believe his own propaganda a bit much.

His refusal to let any writer edit their own comic book (a regular occurrence for experienced writers previously and at their main competitor DC Comics) caused a lot of ill will. Unfortunately he ignored this edict in his own case and thus visited upon the world the horror that was Secret Wars.