Miis should not be playable. Last I checked, Super Smash Bros. Brawl was a game to make Nintendo characters and Sonic beat each other up. The Mii is not a Nintendo character. The Mii is a caricature of you, some annoying celebrity or just every bizarre facial feature available you threw together to try to get people to think you're funny and original even though it's been done one thousand times. This caricature is used in games that don't have characters.