I predict that Kingdom Hearts will have a Dissidia-like game coming out sometimes within two years. Or, at the very least, there'll be an announcement of such a game.
Come on, it's inevitable. I know that the battle system of KH is similar to Dissidia anyway, but I wouldn't be surprised if Square-Enix made a Kingdom Hearts fighter game eventually.
Didn't I mention this already? I don't know when though. Just think, Mickey vs. Goofy. Steamboat Pete vs. Demyx. Axel vs. Riku. Terra vs. Xion. Something like that. Kingdom Hearts is already a mix of worlds, so a Dissidia-like setting would be VERY easy to pull off. They wouldn't even need Cosmos or Chaos. Hell, they'd barely need Final Fantasy characters. At the very least, it could be Kingdom Hearts: Olympus edition. Eh, something like that.
You know the fans would eat this up. I would.