Let's hope that there aren't any more useless characters like Mii.
Miis are going to be one of the most complex characters in Smash history.
Asside from the obvious face customizing, their moves will be modeled and borrowed from other Smash characters, there will be three class designations from long-range to mid to short range fighting, and their power relative to their speeds are determined by height and size (weight) of that Mii. Mii's just might be favored over said strategic purposes, and the only reason to fight with Smash characters is either because of unique moves the Mii's don't have, or vanity.
I'm personally on the side of vanity as my intentions to main all the females is because I prefer to play as a female character. Its why in Mario Kart I always choose Peach, Rosalina, or my Mii and I NEVER stray from the standard kart set of that character because I think they look the best/most elegant, so I refuse to race in any other form, despite the stat benefits I might be losing out on.
If I cared about strategy, I'd probably main a Mii, pikachu, or fox, which is gross, so I'll just main Lucina, Peach, and Rosalina.
Also for the record I think Pacman is a useless character.