A Kingdom Hearts movie is never going to happen. Why? Let me show you the 5 c's.
1. Copyrights copyrights copyrights. There are far too many Disney and Final Fantasy characters to deal with.
2. Cost. $$$$$.
3. CGI. Using advanced computer generated animation will be difficult for Disney characters and other such things.
4. Character Voices. With a game, alot of times they would only record twice then use the best they had. With animation they have to rehearse over and over.
5. Kids. Yes I know that does not start with a c, but you get my point. People won't want to watch a movie, games are far more entertaining and have more out of them.