I know this has been a hot topic in the past, but I don't think an official Features Request thread was ever made. (If I'm wrong, please combine the threads.) For the reasons of accuracy and novelty, I think SMB1 Luigi, AKA this guy, , should be added as a skin. Because skins can play differently, the description can read "Plays exactly like Mario". Most people would say "Just play as Mario then!!!" Again, it's for accuracy and novelty. Nothing more.