Agreed with that. But if Raimi flat out leaves after pretty much confirming he's on board for #4, then it's pretty likely the movie will blow. I would be optimistic if Raimi was an executive producer and/or came out and said, "I had a really good time doing these, but I'd like to try something new and I'll remain on as producer." Unless of course he followed that up with, "Now please welcome the new head of the Spider-Man franchise, McG!"
And wasn't Jake Gyllenhaal all but confirmed to replace Maguire after his back injury almost forced him out of Spider-Man 2?
EDIT
Nolan should never leave the Batman franchise, ever. He fits it so perfectly.