Disney's side on the project has already said that if S-E is willing, they would like to make enough KH games to match up with FF...
But, not only is S-E the one calling the shots on future production, but they already commented that KH2 will be Sora's last role in the line of KH games. So if we see KHIII, we probably won't be seeing Sora, unless it's like an extended remake...
*great idea comes to mind*
Square-Enix should get really smart and rehash KH1 and KH2 for PS3! Keep everything except for the character models the same, unless there are any huge flaws. And then render the character models near-humanly, and PS3 would pwn.
Disclaimer: By the statements I just made I am not suggesting that I have any control over the future of Kingdom Hearts games, nor do I imply that I am somehow in control of Square-Enix.