Well since RE:COM was only remade as is save for the now 3-d cutscenes and voice acting + the use of reaction commands and also the inclusion of Zexion as a boss battle. I'd say it's quite a good game because it was more strategic because you had to think about what cards to use and when to use them, instead of the hack and slash aspects of KH2.
But KH2FM does seem to overpower RE: COM in terms of the addition of replaying Organisaion members already defeated and the ones you fought in COM even though they seem to use different attack strategies between the games. Another plus in the inclusion of new cutscenes, even though I still wished I could've fought Riku with Roxas
New keyblades, new difficulty level and also of course the ability to fight the Enigmatic Soldier aka Terra. So even though RE:COM saw many improvements to the original COM, KH2FM had many more new gameplay aspects added for increased and more enjoyable gameplay.
But it all boils down to personal preference I suppose, card battles or just command driven battles.
Maybe if they make a KH3, they could make battle gameplay like Crisis Core or the newly anticipated Final Fantasy 13