I'm personally not sure if he would be, but he'd go quite well with the whole money/gold theme the game's based around, so his inclusion would be fine by me.
I honstly wouldn't care. I kind of don't like Wario. I mean I don't mind him being in the game, but he's not my favorite character in the Mario series. So if he's in the game cool, if not, it's no big deal.