I think they should make an entire subforum for the wii U version and the 3DS version, each with sub-sub forums like character speculation. Anyway, without further ado, i'll post my 3ds roster. This is not a wishlist, nor a prediction. It is my attempt to make a roster that makes sense and is balanced. It is however, influenced by personal preferances, to a point.
Anything in parentheses is an explanation.
Pokemon:
Pikachu
Scizor (I believe he is the best 2nd gen rep due to immense popularity.)
Hoenn PKMN Trainer (Blaziken, Grovyle, Mudkip)
Lucario
Genesect (I may replace him with zoroark, but I like zoroark more)
(It should be noted that my Wii U version roster is Pika, Jiggly, Kanto PKMN trainer, Mewtwo, and Victini.)
Mario:
Mario
Luigi
Peach
Bowser
LoZ:
Link (with a toon and standard costume change)
Phantom Zelda/Tetra transformation (there is no regular toon zelda phase, because toon zelda never does anything in that phase but shoot light arrows)
Vaati
Tingle
Kirby:
Kirby
Meta Knight
King Dedede
Metroid:
Samus
Sylux
Yoshi:
Yoshi
Baby Mario Bros.
Mario & Luigi (counted as it's own spinoff):
Fawful
Wario:
WArio
Fire Emblem:
Marth
Lyn
Misc.:
Muddy Mole (I may replace him with the Prince of Sable)
G&W
Starfy
Isaac
Fox
Lucas
Ray
Pit
Jill
Mii
Flipnote Frog (A moveset has been made. I put it in to represent DS applications, and as a surprise character.)