Now, we all know this is being done because Slott sees himself as Doc Ock (he has said as much in several interviews) and this is more a boost to his own self-esteem as any desire to build story lines, but if his goal is the redemption of Doc Ock by way of Peter Parker, then Pete has to come back. Follow me on this. Peter "rewrote" Ock's memories and motives at the end of #700 and in Avenging 15.1 we see Peter's tendencies causing Ock to act differently than usual, like stopping the purse thief. From everything Slott has said, he wants Peter's character to overcome Ock's past and create this new hero and carry on Peter's legacy (I still think this is a terrible way to do it but whatever). But here's the problem with this happening and Ock becoming the permanent Spider-man... Peter's character and understanding of right and wrong would never let this happen. Peter is totally, 100% against the death or suffering of an innocent person, especially one he cares for. He even made a deal with the Devil to save the life of an innocent, Aunt May, at the expense of his one true love. Right now, Ock is still arrogantly boasting about his victory over his mortal enemy (which feels dirty to read in Avenging) but if Peter's character continues to reshape him, and it has to or you have evil Ock taking back over and Spider-man becoming a super villain, then Ock will have to get to a place where he feels immense guilt about Peter's death at his hands and work to find a way to right that wrong (through the golden octobot, a clone, another deal with the devil, etc). I know comics don't have to follow logic, but if Slott's ultimate goal is the elevation and redemption of Doc Ock then it has to logically end with him sacrificing his life for Peter's in more than just giving up being a bad guy and becoming a good guy.
But if he's continued to have free reign to do whatever, Slott will find a way to keep his love affair with Ock going strong while crapping all over Peter Parker and Spider-man fans.