Super Smash Brothers - What makes them so special?

Could have been worst…

"With the Wii Fit Trainers, the male and female Robins, the Villagers, and Little Mac, varying their appearances and voices works just like selecting alternate color variations. However, whenever there is even a small difference in abilities, that character gets an actual roster slot."
I'm cool with this justification for clones, personally. But it's cool if others aren't, so long as they don't complain about how "DARK PIT AND DR.MARIO TOOK AWAY MUH RIDLEY."