Most Likely not happening, but if it was, what new pixar and Final Fantasy world would you like to see in the game?  
 
For me, Pixar --> Toy Story.  Sora and Co. will reduce in size kind of like in Alice in Wonderland in the first game.  Sora could be an action figure, donald could be a stuffed animal, etc.
                  FF --->   FFX universe.  I guess b/c that's the game I've been most attached too.

Prince of Persia.  Hey, the films are a Disney property now, right?

I don't know if all of them are.

Well, for me, I would like the world, Notre Dame, from the movie, The Hunchback of Notre Dame.