Avi Arad vs. Tom Rothman - Who's Worse
I bring them up because both in recent years, have grown a bit of a reputation of being meddling executives in relation to Marvel's TV shows and movies. I don't feel that I need to go into much detail right now about Tom Rothman and company over at Fox.
As far as Avi Arad goes, well he did force Sam Raimi to shoehorn Venom into Spider-Man 3. This was despite the fact that Raimi made it known that he didn't like the character. Also, Raimi was already planning on using Vulture as the "third" villain to go with Harry Osborn/New Goblin and Sandman. Vulture (Ben Kinglsey was a top canidate for the part) would've been a cellmate of Sandman's. Vulture would apparently, want revenge against Spider-Man for putting him away in the first place. He also would've acted as a guilty conscience for Sandman. This would've on paper been a lot more plausible and coherent than the heavy-handed, crammed mess that ultimately became Spider-Man 3.
Not only that, but Avi Arad was also the main reason why there was no six season of the 1990s Spider-Man animated series. This was despite the fact that the show was still very popular and had a lot of loose ends (such as Mary Jane Watson's disappearance). However, the head of Fox Kids, Margaret Loesh had an ax to grind with Arad. Therefore, after the 65 episode contrat was complete, Loesh outright had the series canceled and the animation house, Marvel Films, shut down.