Well if he uses his powers to get back at everyone, using them for "revenge," I think that makes him a really interesting "Bad guy." He is sympathetic, but really, how interesting would it be to see Spider-man fight a guy who just steals money and kills for the sake of it? We had that with Green Goblin in SM1 after he got revenge, but there is only so much you can do with that.
Haha. It seems like a good am ount of the posters here want an "uninteresting" villain.