I think it's more 'easy' than 'dumb'. I like the mechanics and control; it's more easily accessible to perform specials and air juggles especially. Every character seems more balanced, too. It's not the best, but it's fun.
I don't particulary like the physics, however, because it seems too floaty and everyone is flying (or maybe it's just me). It also seems that some characters (like Amaterasu) are too small to hit with regular attacks.
I wish the roster was larger. There were 56 characters in MvC2 and I think there are 36 in MvC3 (plus DLC). I'd love to have had Franziska von Karma, Godot, Klavier Gavin, Rockman X, and some Rockman/X Robot Masters as playable characters (^__^,)