Kingdom Hearts 1. I think it had the best functionality of the magic systems and worked wonders with donald and goofy's abilities... donald magic beeing stronger was because he had more maximum mp, and goofy had the mp gift. And then the abilities like mp rage worked, in kh2, only if there was still blue mp, not on mp charge, that was not an issue for kh1... maybe a mixture of both would be the thing i love the most... not difficult to execute but hard to imagine one
For Sora, the system in KH2 made a lot of sense. Sadly though, it felt pretty useless for Donald if you ask me.
A mix of KH1 and KH2 would probably be the best in the future, because both had their good and bad sides.
Definitely KH1. I guess KH2 would have to come next since most of the other games use cards/command deck, but its magic system was awful. I think they made it the way it is there to balance out the Drive system, and since I disliked Drives in general, it only made magic feel unreliable/useless because the MP bar was always loading.
I think kh2 had a more 'creative' style. The fact that your magic reloads over time is quite new. It gave a more active combat, though it did make using magic very easy. Perhaps a longer bar and slower regeneration (kinda mix with the kh 1) will provide with better balance?
I remember actually using magic in KH1, whereas KH2 you really only needed Curaga and occasionally Reflega and Thundaga. And, of course, KH1's magic didn't easily regenerate, so frugality was key, whereas KH2 was so easy you didn't have to worry about strategy as much.
My favorite magic in a Kingdom Hearts game was in the original. I enjoy that landing hits builds your magic back up. It can get intense during tough battles -- actually having to land hits in critical condition to cast Cure. Y'know, instead of simply being able to wait until it manually reloads. Spam dodge roll/super glide to win! I also don't like how Cure consumes all of your MP in KH2. It just makes the other spells (except Reflect) seem that much more useless. I enjoyed healing/buffing my party members individually and still being able to cast an attack spell if need be.
The MP system was best in KH1. I actually found the system in KH2 more frustrating and harder to utilize than KH1's, since the moment you Cure, boom, magic is gone. I won't go further on that subject though, since everyone has more or less touched on what made the KH1 magic that much better and useful.
That being said, KH2 had a much better version of Fire (Firaga especially), Reflect was pretty useful in the FM fights, and the Magnet line of spells from the series are wonderful, especially if mixed with Mines or Balloons.
Ideally, I'd love for KH3 to have the MP system from KH1, but give us a wide range of physical and elemental magic we can equip and choose to use from KH2, BbS, Re:coded, and DDD. Zero Gravity was much better than Gravity, if you ask me, the Surges saved my life SO MANY TIMES, etc. Meanwhile, certain abilities should be Limits again instead of just abilities (though some being shotlocks is also fine).
I have to disagree about Fire. I liked that Fire would automatically follow your target in KH1. In KH2, you have to let the enemies surround you before it's useful, where usually I would just jump and avoid any damage....