It's important for story reasons but the cutscenes are already complete. And, to be frank, a lot of the actual *game* side of it could use some serious work (like FlowMotion breaking a bunch of the level design and not flowing directly into your combos in the way that melee/deck abilities work seamlessly together, Reality Shift being kinda sucky and unfun, and like every single thing involving the Dream Eaters).
Honestly, they could just port over a bunch of stuff from Birth By Sleep (like command melding and the superior passive-ability system), make the Dream Eater leveling solely about their stats so the touchscreen minigames could be 100% removed, and you'd have a much better growth system, eliminate a vast amount of the touchscreen nonsense, and generally streamline gameplay to be all about finding the Dream Eaters you actually want fighting with you in your party (and building them with good stats) instead of choosing the ones who offer Sora the best passive abilities, and all simply by looking at precedent in the series rather than requiring RPG-design expertise. *shrugs*
If they wanted to address the general lack-of-content problem that the game has and add a bunch of superbosses and stuff that's another thing, of course.
There's also likely no fixing the Drop system, but if the other issues with the game were taken care of it'd feel a lot less grating (and maybe they could extend the base drop time by 50% or something, though I honestly never had a huge issue with it).