I definitely think that there shouldn't be any RNG element of getting finishers/command styles to become available (if that's actually the case in BBS 0.2).
I'd much rather it actually function kind of like Sleights in Re:CoM but without the card system; like, ground finisher/ground finisher/ground finisher or air finisher/air finisher/air finisher would always produce a result based on which Keyblade you have equipped (for example). Fire/fire/fire for firaga, fira/fira/fira for firaja, firaga/firaga/firaga for firaza, et cetera, but also stuff like fire/fire/ground combo finisher for a fire-based command style, firaga/firaga/magnega under normal conditions for firaga burst, firaga/firaga/magnega *while in the fire-based command style* for megaflare, and so on. Consistency is key with this stuff if there's actually to be a strategy element to it, IMO (and I'd love for higher difficulties to be all about skillful moment-to-moment action-gamer play *and* successfully comboing your way up to finishers that'll maximally exploit the weaknesses of whatever you're fighting).
I feel like if they nailed the physics and the stun/juggle/armor break mechanics, a system like that could reach an unprecedented level of depth for ARPGs.