To be honest, I think online play would kinda suck anyway. The whole point of it is to be raging at your friends in the same room, because they just jumped on your head and sent you to a lava-filled fiery doom.
Then you get pissed and try to strangle your friends with the nunchuk, and they fight back by hitting you over the head with the Wiimote.
Sounds like more fun than getting owned by some cocky 12-year old on the other side of the country.