What the heck? Am I the only one who thinks Miis would rock? They'd all have the same moves...you just pick "Mii" as one of the characters, and then choose which Mii you want it to be in a submenu, not unlike choosing your name.
They'd all have the same moves and probably the same height and weight, but otherwise you could fight with Chuck Norris, Jesus, and Hitler in a Brawl match!
It's all these outrageous suggestions that you know would never make it into a Smash Bros game, like Chuck Norris or James Bond, but with Miis you could! And it'd be a representative of the Wii generation of Nintendo, besides Twilight Princess stuff.