I don't think we're going to be seeing the Black Cauldron characters seeing as how a) They're not very popular, and b) llyod Alexander's family still retains the rights to the property and wouldn't be likely to to give permission to use the characters for further projects. Of course, Tarzan being owned by Edgar Rice Burroughs didn't stop them, but of course, the Tarzan movie actually made money.
What would I like to see in KH2? Lemee see... well what do you know, all of my picks are based on books as well.
The Hunchback of Notre Dame would be interesting if only because you'd be fighting against the church, not that using ecclesiastical themes has ever stopped Square before. I just want to see how the cathedral would be rendered.
Kimba the, I mean The Lion King's an obvious choice. Lots of popular characters, neat settings (Pride Rock, Elephant Graveyard, etc.) and the fact that everyone in the world liked the movie. Here's to hoping they can secure the rights to use the Zimmer score.
Robin Hood is another easy choice.
I think the rescuers Down Under would be fun to do, especially if the party is NOT shrunk down to mouse-size. Helping the two mice do whatever it is they need to do would be a useful mechanic, and Joanaa, McLeach, and his half track make for some really phenomenal boss possibilities. Sorta reminds me of the Tarzan level boss.
The Sword and the Stone is another easy pick, but it would be midaevel overkill to have both this one and Robin Hood. Endless possibilities here as well, particularly if Mimm is a boss and turns the party into different animals with different characteristics throughout the fight. You could do the same thing with an Emperor's New Groove battle with Yzma.
What I'd REALLY like to see is for the 2nd Kingdom Hearts, which has already been established as being darker and less cartoony than the first game, to focus entirely on Disney's live action efforts. It probably wouldn't have the appeal to consumers that a cartoon-based game does, but merciful heaven, just think of what you have to choose from here!
20,000 leagues under the sea
Swiss Family Robinson
Zoro
Mary Poppins
Bedknobs and freaking Broomsticks, baby!
Teasure Island
Davy Crockett
TRON
Swamp Fox
The Black Hole
Flight of the Navigator
Honey I Shrunk the Kids
Pete's Dragon
You know, looking at the above list, you could actually design the second game as a journey through time rather than through different, dispirate worlds. I've even got a title for it: "Sora and Riku's Excellent Adventure".
Now, I realize that the chances of that happening are slim to none, but you have to admit it'd be a pretty wild ride. And don't think for a second that the graphics wouldn't look realistic enough. Square is more than capable of producing photo-realistic graphics, even without the budget they had for the deplorable "The Spirit Within" movie. Anyway, that's the kind of game that would make me happy.
Aw heck, just base the whole darn thing on Bedknobs and Broomsticks.