You're kidding right? Jungle Hijinx, Orbital Gate, Wuhu Island, Pilotwings and Kalos League all look perfectly playable.
I would love all those.
Jungle Hijinx seems fine to me.
Orbital Gate would be an issue, as you can die if you don't respond quick enough.
Wu Hu island/ has Walk Offs most likely, plus swimming/drowning.
Pilotwings looks great to me.
Kalos League has actually damaging capabilities.
One could argue that stages that have characters stop fighting to focus on another aspect of the game (getting up on the top platform to avoid damage after taking off on WuHu Island, Orbital Gate.)
I can already see someone complaining that it wasn't fair the stage took off because he was in landing lag from a down air and couldn't react quickly enough.
(Personally, I would just argue that's his own fault for attempting the move after its been clearly noted the stage is going to move/change.)
I'm all for these stages though, but those will most likely be the argument.