well character creation would not make sense for this game.
i would like a longer adventure mode but not to much longer cause thats the fun of the game that you can sit down and play it really fast if you dont have alot of time to play
as for story it kinda has one the master hand is making them fight
i agree with the battle rooms thing. but remember friend codes so that wont happen but i dont mind the friend codes.
my biggest wish is that after you battle online it lets you speak with the people you played against so that you can make friends to play with and not just random people all the time