Having alternate movesets would be a pain to balance out, and it would be hard to do because the mechanics are different than in previous games, so even if fox had his melee moveset, he won't be able to do wave shine. In addition, focusing on this would be like creating 4 times the amount of characters and giving less emphasis on the new characters, and it would be awkward to have the 64 characters to have only 3 B moves. If anything, they should just add the alternate costumes. If Sakurai wants the characters to be more like their melee counterparts, then he can just choose to make them that way.