According to rumor/legend, the Urban Champion was considered alongside the Excitebiker, Balloon Fighter, and the Ice Climbers (and maybe Pit) as candidates for Super Smash Bros. Melee, to represent the NES era. The Urban Champion was debunked because there wasn't enough going for him to be a unique character.
Now, I haven't played the game, but it sounds like all you do is basically punch each other until one of the fighters falls down a manhole. That's... not really that much to work on.
Having said that, I'd totally welcome him, being a character from a game that's all about fighting, though I'd have other choices I'd rather see before him.