A new numbered addition to the Kingdom Hearts series long overdue. With that Final Fantasy Versus XIII being cancelled, Nomura can devote his resources to making a new Kingdom Hearts game. It would be released for the Wii U, 360 and PS3.
Worlds:
One issue that the KH series has been critisized for is the recycling of old worlds from Disney's universe. For the new game the developers should focus on the seires of Disney Afternoon. Shows such Darkwing Duck, Tail Spin, Duck Tails, Goof Troop, Gargoyles, and Chip and Dales.
http://en.wikipedia.org/wiki/The_Disney_Afternoon Minin the Pixar movies for worlds would be a good idea as well.