If we're really, really lucky, they'll add Kurt Zisa and Xemnas to the Coliseum so we can re-fight them (and have the assorted super-bosses drop Defense Up, Attack Up, or AP Up). It bugs me that those two are way more interesting than the Ice Titan, and arguably more interesting than Sephiroth, but you only get to fight them the once. Heck, I'd love to be able to fight Riku 2 again, too.
I figured the extra skills in that video were just for demo purposes. (It'd be kind of boring to have nothing but the basic attack command in a demo)
New Game+ in KH1FM would be great, especially if it let you carry over abilities. It'd circumvent the issue with potential Level 1 runs too, in regards to essential abilities like Guard.
I'd want it to carry over Keyblades, accessories, and abilities learned via leveling, but none of the abilities learned via story progress or Dalmatian progress. (So you'd need to get all of the magic and all of the special attacks back).
Keeping your customized Gummi Ship would be sweet, though. Make the lead up to finally unlocking the Warp Gummi a lot more tolerable.