Single player looks pretty amazing. They didn't integrate anime cut-scenes that well in the old games.
I can see why they changed the L2/R2 buttons so that if you wanted to block you wouldn't accidentally substitute, but it also means that if I try to substitute and fail, I cop it all in the face instead of a block like it used to. I haven't tried pressing both buttons yet to see if that had the same effect.
Tsuchikage's pretty fun to use, but I didn't like Mizukage at all.