Electro... Always been a dick.
Rhino... Got super smart in that Webspinners anthology during a Tears for Algernon homage... And in Death's Head II, in an alternate future timeline, not only was he a good guy, but She-Hulks boyfriend.
Scorpion.... Always been a dick.
Kraven... He hunts people for sport, but he's independently wealthy, so it's really questionable if he is wanted by the law as a super villain if he's not the type to rob banks.
Green Goblin... The Iron Patriot? In the current animated, Norman was sane and cured, and the Patriot was a sincere attempt at being a good guy until he got Goblined up again. Moonstone was screwing with his meds (Warren Ellis was writing) when he was running the Thunderbolts because it was funny to watch his poles blink back and forth... Recently in the comics, the Goblin Juice was taken from his system, which might mean no healing, and no super strength, but: "Just you wait Spider-Man! You have no idea what you have unleashed! You've never fought the real Norman Osborn before, just some deranged mentally unstable incompetent. I will destroy you!" (Shakes fist at a crack of thunder.)
Vulture. Always been a dick. There have been other Vultures. Most were still also bad, but I think one of them was a goodie. They didn't last long. I think Adrian literally ripped one of their faces off while diving at him at 200 mph.
Mysterio... Always been a dick. Dicks. There have been a couple blokes under the fish-bowl.
Venom... Eddie thought he was a hero? Flash is a hero.
Sandman... He was in the Avengers, and then Doctor Octopus? Someone (John Byrne!) tied him to a chair and brainwashed him into being a super villain again. Sandman is in prison with Ben Grimm presently in Fantastic Four. There's a possibility of a new heroic streak in the guy, since Ben is on the ropes and needs a friend.
Boomerang's Sinister Six in the Superior Foes of Spider-Man is a laugh and half. Still bad guys, but they are just such epic fuckups that you have to silently root for them as they cock up into a new series of bizarre cross purposes each month.