Stopped reading at Goku. Which I assume a lot of other people did too, didn't read through the comments.
If you want Goku go play as Evil Cole and activate Level 3 and imaging him with a severe case of diarrhea.
Traveler would be interesting but i still think it'd be a stretch to make a full moveset for him. Spyro and Amaterasu are both deserving and would add nice gameplay variety. Chell i dont really think could fit in. I know people have made really good movesets for her, but i just don't see her as a fighter. Goku, i wont say anything because i dont know him, but i have to question whether he has any place being in this game.