Definitely need to reduce the number of villains. Originally Raimi wanted to just have Sandman and it was the producer's idea to add Venom and Gwen Stacey. He also didn't want Harry to go full villain but rather become "somewhere between" where he was and going full Green Goblin (which is what we got).
So basically just have less interference. Personally I don't really like Sandman as a villain and would have the rumor come true where Ben Kingsley was supposed to play the Vulture. Raimi wanted the Vulture and Sandman both in the movie.