It's just over five years since Kingdom Hearts 2 has been released and we haven't heard a peep about Kingdom Hearts 3. If you're willing to take in any sort of plot details about KH3, you'll be finding them in Kingdom Hearts 3D.
Kingdom Hearts director Tetsuya Nomura teases Kingdom Hearts 3D contains clues about the third entry in the main Hearts series, which might be revealed in a hidden movie. Nomura did confirm Kingdom Hearts 3 completes the Xehanort saga and will keep Sora around so he can continue his hero gig in future titles.
According to Nomura, work on Kingdom Hearts 3D is nearly halfway complete. A release date for Japan or elsewhere has not been announced.