The problem is that you can't join a race. If the game would send you to any race that is on the little number of players wouldn't be such a problem.
Now you will have to wait in the menu that other players are looking for a race in the same time... then if you want there to be 4 players or more the other people get tired of waiting and leave. Then you start with 3 players and soon they both leave. Then you have to start the whole process all over again.
I'm pretty angry at nadeo that they released this game with this kind of sucky multiplayer concept. I dont think that it's even possible to release a patch for a Wii game but if it is that is the least nadeo could do.
I just want to play online is that too much to ask?
Firebrand developed the Wii and DS versions of Trackmania, not Nadeo (Nadeo is mentioned in the start-up of the game, but that is probably just because they invented the concept.
Maybe there will be an improved Trackmania Wii 2 someday, (bearing in mind Trackmania DS 1 had no multiplayer at all), but it is indeed a shame that the current Trackmania Wii is so restricted (which will put players off in the long term).