Well, again, Peter's not making out with Gwen behind MJ's back. This takes place six months after the events of Ultimatum--a lot can happen in that time. I really don't get why everyone's assuming that he's cheating on MJ.
Regarding Shocker--I don't know if you've read the recent issue that explored his character and made him fairly complex and threatening? The whole point of him being treated by a joke beforehand was to lead up to a point where he just exploded.
Kraven--fair enough, but I really think the only time he was ever a serious villain in 616 was the Last Hunt.
After his initial appearance, the Green Goblin was far more than just being the Hulk, character-wise.
Doctor Octopus only got the magnetic abilities later on, and that was because his early tentacles were destroyed. So he basically made new tentacles out of the scrap metal with his abilities. He's not the master of magnetism or anything like that.
As for Venom, I thought Bendis's take on him was far more interesting than the 616 version. And when you get down to it, you could argue that the original origin for Venom is pretty needlessly complicated as well, even moreso than Ultimate's.