At least when Peter died in ASM #700, he still went out a hero, even if it wasn't dignified. But to have him "die" again, but this time in utter disgrace, a man who in his darkest moment would risk (however briefly) a child's life in order to save his own? This disgusts me on a visceral level. Because that isn't who Peter Parker is, and if Slott doesn't know that, he has no business writing Spider-Man.
I could believe that Peter could lose it in a moment of anger and kill someone. A story like that would require a writer with a deft touch, but it wouldn't destroy the essence of the character. But even if Ghost Pete was just an echo, having any version of Peter Parker risk the life of a child to save himself is deeply wrong. It goes against everything the character stands for. It's character assassination plain and simple, and all to prop up Ock as a "hero."