It also screwed up some other stuff:
It is now revealed that Harry Osborn never died back in 1993, but his father saved him and had kept him locked up in Europe until he felt it was right to revive him totally.
Originally, Norman's motivation for planning the Clone Saga and returning to duty as the Goblin was to get back at Peter for "killing" Harry (back then, Norman really DID love Harry and was PO'ed he died fighting Peter). Now, since Harry never died and Norman knew it, why did he come back to torment Peter?!