I already got the Japanese version (just happened to find it very cheap on a second hand site).
I am still going to get the English version on release since I want the limited edition and I want to beat the games on critical, which is not possible for me since I cant read japanese.
So far I am really enjoying KH 2 FM. I am now at the 2nd visit of beasts castle (vs Xaldin). The only downsides I could find so far are the faces in some cutscenes are still painted on rather than animated, some remastered tracks are...meh, and finally THE EASY WAY TO LEVEL MASTER FORM IS GONEE D: The trick in the land of the dragons doesnt work anymore :C
Other than that, all is awsome.