Who do you think was the hardest boss?

For me it was definitely the 2nd Riku because you only have one way to cure and that is the Oogie Boogie card - and you can only do it once.

Ansem(2nd time) came close to the hardest, but you can heal yourself multiple times with mickey and the Oogie Boogie card.

Not any bosses in Sora mode were as hard as those 2 for me.