Metal Overlord
Smash Hero
Coming from someone who would like Mii's in Smash, I wouldn't say that Mii's are important characters to put in Smash 4 based solely on the fact that their series is popular. There are better reasons to put them in than just sales (since they'd basically function as the "customizable character" of Smash and that they are pretty much synonymous with the newer-gen Nintendo consoles, being the Nintendo equivalent of Avatars for the Xbox 360). Smash may be about featuring "Nintendo's All-Stars" in a fighting game but that shouldn't be an excuse to shoehorn in characters just because they're popular