It's come to light that there will be no new characters in Super Mario Bros Wii, meaning what we all saw at E3 2009 is the entire line up, according to what Miyamoto has said recently;
When asked about the playable characters being Mario, Luigi, Toad, and Another Toad, Shigeru Miyamoto says "That's it."
If it's true, it's pretty lame to the point of being comically bad, cosmetic or not, a selection of characters to choose from is what fans will naturally expect from this game, so why on earth is it limited to this very weak selection. Maybe just maybe he's adhering to the official company line so far, but it's hard to tell...
Thanks to Infendo