No DLC on the Wii version actually makes sense for the same reason as no DLC on the PS2 version and it's not because of lack of storage. Unlike the 360/PS3 versions what goes on in the backgrounds during songs isn't realtime, it's FMV. Every song in the game has it's own FMV which in and of itself shot the game disc size way farther up than it would've been otherwise. Guitar Hero 3 Wii isn't dual layer, Rock Band Wii will be which approximately the same number of songs at launch. If the DLC was just the song with the model animation data like it is elsewhere that would be one thing, but with this and the PS2 one it would be the song, AND it's video which depending on the quality of the footage could range from anywhere between 50 and 70MB just for one song. That's just not gonna happen, especially on Wii.
So now instead of downloading it, we're getting the DLC in DVD form. Meaning we are STILL getting the songs, except you may have to disc swap. So WHAT'S the problem again? *rolls eyes*