I feel a bit sad, even with the trailer (and the seemingly upcoming info this and next week). I like him despite aaaaaall his flaws, and this project was like his child (maybe not as much as KH, but well).
So, yeah, I'd like to think he left his position in order to avoid KH III having the same fate, but deep inside I think there has to be something besides that (problems with executives, inability to direct, tiresome...)
I hope he doesn't leave the company after KH III like some people have said
People might dislike or hate him, but it is obvious that he's been a very important part of the series for years and that he's got loads of talent. It just has to be controlled by someone in order to work.