It'll be interesting what Nomura will pull of with KH3. In my opinion, KH3 will be on the same scale as XIII, or even Versus for Square, so obviously they really want to do a good job.
I'm really hoping that with the ps3 engine (or ps4 who knows?) they'll really be able to improve of the things that have lacked in all kh games to date. I hope to see disney worlds that look stunning. Perhaps some worlds that love very cartoonish, with bright pastel colors, while others going for a more realistic jungle look (say the jungle book, and having a lush Uncharted 2 jungle feel). I hope to see real towns, with various pedestrians. I really do think that they can create real breathing worlds, that feel ALIVE, and truely animated.
Once they do that, and take what they've learned from BBS (the complex, and addicting combat, oppose from the random button mashing in previous kh games, to Disney characters actually taking part in the plot, like in kh1.) then KH3 could truly be on the brisk of epicness.