And I'm going to post an awesome theory I just read bythe king of ASM 700 and Superior Spider-Man theories. This latest one is a real killer.
Another thing I hadn't considered is what if its amnesia. According to BleedingCool Dr Strange is somehow involved with Superior.
What if Dr Ock after finding out Peter's identity as an act of revenge sends a message or broadcast to the entire world (like he did in 600 he hacked all the computers and TV's to broadcast a message using octobots) that Peter Parker is Spider-man. Ock is apparently assembling a lot of villains for 698 what if this is how he does it. This causes Dr Strange's spell to break so everyone everywhere will know Peter is Spider-man (as Strange said this is what would happen). So suddenly Peter is beset on all sides by his enemies who now remember who he is. They come to attack him all the way untill 700 when Peter goes to Dr Strange to ask him to do the mind wipe again. Strange has already said this was to dangerous to repeat but Peter convinces him to do it.
As Strange is doing the spell to make people forget something goes wrong just like Strange predicted and instead of simply masking Peter's identity to everyone it erases Peter completely from their minds. No one ever knew he existed including Strange (his spell worked on himself and Peter). Peter is now stuck with no identity but Spider-man. Has no idea who he is and because he has no memory doesn't remember the "with great power comes great responsibility" line so he will no longer have morals to restrain him.
Peter Parker is no longer Spider-man as Slott said because Peter Parker doesn't exist only Spider-man. Mary Jane and Spider-man are free to try and find each other again. She would technically only be dating Spider-man because Peter Parker doesn't exist. Everything ends in a flash of gold like Madame Webb said as that could be the Octobot that televises Peter's identity across the world. the picture of him speaking to his Uncle Ben in that preview by Wacker may not be his death but simply his psyche talking to him telling him not to forget who he is (which is then followed by the mind wipe). Peter would now not know who he is hence the name of the first issue "Hero or Menace" because he has no recollection of who he was he'd have to make a moral decision based on nothing at all about whether to be a hero or a villain. There's no Uncle Ben to guide him this time so the choice is on him. We already know that Peter before becoming Spider-man was capable of being an a$$hole (letting the burglar go for example) this would take Spider-man back to that time where he had no moral code thus explaining the brutal treatment of his villains.