REGISTER TO REMOVE ADS
Well, we'll probably need all of this. You can see from the trailers that the Heartless have new moves. Shadows have that swarm, the Yellow Opera and its subspecies have that ring, huh, thing they now do. I'm even betting we'll meet upgraded Darksides and Twilight Thorns. Heck, I'm even hoping we'll fight a Darkside and Twilight Thorn at the same time.
We also have the new Organization XIII, and I'm sure that with the PS4 capabilities they'll be able to do lots of cool new things that will require powerful moves to counter.
It could also depend on things like your location. From the Jump Festa 2016 trailer, I have the impression that you may need to be close to a body of water to summon the pirate ship (when it was shown in the Kingdom of Corona, Sora activated the ability while inside a lake).We still have no idea how to trigger certain abilities like the Attraction Flow. Sure, in trailers it looks like we can just activate it at will but maybe there's more to it or maybe you can't even take all of that with you at the same time. (I could imagine a Final Fantasy VIII-ish system where you have four (or maybe eight, like in KH2) spots in your command list and you can't always have everything with you.)