What Character would you like to see in a Smash Bros Game?

[Kriven]

and even consider a Yoshi-Koopa hybrid to be a canon character in the Mario universe.

Isn't Yoshi actually supposed to be some kind of Koopa-related creature? His saddle is really a highly stylized shell (it's even stupidly round in some games), and he's the only "good" character capable of using the Parawings.

I'm pretty sure I remember an interview where Miyamoto talked about Yoshi as being a "good Koopa". At least during the conceptual stages.