I've been doing a bit of looking around and I've heard a few things.
There's apparently a fix for people who can't connect to matches on their first profile. Just create a second profile, connect to a match with that, quit the match, then go back into the first profile and connect with that.
But then there's people like me who are still unable to connect at all, even trying this fix method. Closest I got was joining one free-for-all match where I got to the bit where it was loading up the map, but then I got an error saying it couldn't connect to the server and dumped me back to the lobby screen. But 90% of the time the game is just freezing while attempting to find a game to join. When it freezes it loops the same three seconds of background music that's playing at the moment the crashing occurs. Anyone else been getting this at all?
According to someone on GameFAQs there's server problems with the Wii version, but I don't know if this is true and has any bearing on my problems I'm having. This is about all I know, if anyone knows anything that would help, that'd be great.
If it's necessary to know, I connect via third party LAN adapter. It works with every other WiFi game I have including MW Reflex and GoldenEye. I might just try wireless WiFi and see if that works, but I've loaded the game about 15 times now so I'm gonna try it later.