>it has less than 12 characters
It was only a problem in Skullgirls because they were aping fucking MvC and letting you bring half the cast into a single match.
Otherwise 12 is fine. 10 is fine. 8 is okay. Less than that and it's not going to be regarded as the best iteration of the game, that's for damn sure.
Nakaoka is quite a qt though Higuchi and Tatsuno are good backups.