With quite a bit of dialogue that "sounds so familiar".

KEYBLADE FORGE

In the Keyblade Forge, you'll sacrifice two (maybe three) Keyblades/Keychains to make a stronger one (Kingdom Key ineligible). As you're only given one of each type of Keychain, the only way to discover every possible combination is through D-Fusion.

GUMMI PLANET

A world that requires Gummis to explore. As the team will be in the cockpit, the Gummi vehicle will count as the team. Blueprints include speeders, tanks, and mechs.

CHAIN REACTIONS

I don't know if something like this has already occurred in BBS or 3D, but reintroducing Reaction Commands, Reaction Chains occur like the Renzokuken or more likely similar to the auto-scenes in Dark Cloud (causing Sora to do a complex stunt rather than a series of hits).