In an interview with series director, Tetsuya Nomura, it was mentioned in the Birth by Sleep Ultimania that:
There are 3 new Kingdom Hearts games in development including KH3 which is in the conceptual stages. One will be released this year, the other will be released next year and will focus on multiple main characters.
Kingdom Hearts III will be the end to the Xehanort Saga but not the series which will continue on with Sora as the main hero.
Previously there was a rumor of a Kingdom Hearts Another dive for the PS3 which focuses on another individual other than Sora who was also a main character of the series. My guess is that it means either Riku or Xehanort since it has been called "Xehanort's Saga". Seeing Xehanort's side of the story would be interesting. I highly doubt it will a Mickey game with Epic Mickey coming up.
I guess we'll see more about the other KH game this year at E3 since TGS would be a little late for a game that will be released this year.
Direct quote:
About the next title, Kingdom Hearts 3 depends on Final Fantasy XIII Versus, but development of the next title is already underway. There are two titles other than Kingdom Hearts 3 in conception, and I think I’ll release one within this year.”
“As from next year, I want to put out a title with multiple main characters.”
“The series won’t end in Kingdom Hearts 3, more like the conclusion of the Xehanort saga.”
“It’s not the case that when Sora’s story is over another hero’s story will begin; Sora will be the hero until the end.”
http://heartstation.org/?p=2093
