I actually made a design document for a theoretical Smash Bros. DS back in 2004. I had the roster be at the same size as Smash 64's, yet the roster was profoundly different. Returning from Smash 64 and Melee was Mario, Link, Samus, Kirby, and Pikachu. From Melee there was Bowser, Mewtwo, and Ganondorf. I had four newcomers: Wario, Meta Knight, Ridley, and Toad.
Yes Toad. I had a sort of hero vs. villain/rival theme going on with the roster. I went with Wario, Meta Knight, and Ridley obviously because those were among the Top 5 most wanted newcomers at the time. I threw in Toad because I honestly thought of Wario's Woods before Captain Syrup, and I thought Toad would have been an interesting fighter with various motifs from Wario's Woods and Super Mario Bros. 2.
That nine years later that Toad looks like he got shut out again is deeply disappointing. There are few other fanbases left out there that have been as long running as Toad's has been (Ridley probably be the only notable example there is of a character that had extensive support during the pre-Melee days that still has a lot of support today).
Toad certainly deserves more than being a special for Peach. I think he may very well be one of those character whom will never get in so long as Sakurai is the one deciding the roster.