I've just flipped on the "geek out" switch on my computer so I could say this: Goku would be...uh...a cool character in the next Smash Bros. Yes, there are several reasons why he shouldn't and couldn't be in the next game, but who cares? Goku for the next Smash Bros.
Goku is a crazy 'roid monkey who can't be killed by conventional means. The only thing that can kill a Goku is another Goku.