Speaking with The Wrap, Waititi says he's not directing Guardians 3, but he's not done with the MCU just yet...
“Nope. Not doing that movie. I’m hanging out with [Marvel] still. Talking about new stuff, but I don’t know what that might be yet. I want to do another movie with them.”
In a further statement (via Deadline) he talked about whether he had conversations with Marvel about the gig at all...
“I didn’t really. For me, those are James [Gunn]’s films. Going into something like that with his stamp all over his films, would be like going into someone’s house and saying ‘Hey, I’m your new dad, and this is how we make peanut butter sandwiches now.’ It feels kind of awkward.”
Certainly, there will be other directors out there more than happy to jump at the opportunity. Whether Marvel wants to go with someone less-experienced is another story. Could make things tough if the popular choices all feel the same way about replacing Gunn.