Supposedly the same source that leaked Wii Fit Trainer, Villager, and Mega Man (alongside Little Mac, Mii, and Pac-Man), said that additional newcomers include "Chrom, Palutena, Shulk, Chorus Men, and a Pokemon from X and Y".
12 newcomers for Smash 4 sounds like a solid amount, especially with the amount of time left between now and Smash 4's summer release (possibly September or August).
What is interesting is that although there were a lot of surprises, there was barely any characters on it that were "popular". Pretty much only Mega Man, Little Mac, Palutena, Shulk, Chrom, and to a lesser extent Pac-Man would be construed as popularly requested.
Even more curious is how veteran franchises basically got shafted. Rosalina, Greninja, Palutena, and Chrom being the only four veteran series newcomers sounds a bit underwhelming.
The one plus though about this 12 set of newcomers is how many new Nintendo franchises got represented. Punch-Out, Animal Crossing, Wii Fit, Mii, Xenoblade (stand alone), and Rhythm Heaven all got playable characters.
Even more curious is how few of the characters were characters that existed as popular requests prior to 2010. Pretty much only Mega Man and Little Mac fit that. Pretty much only Little Mac and Mega Man would be the only two characters that were popularly requested during the pre-Brawl era, that managed to get in as newcomers for Smash 4.
Hmm. I wonder how many people are going to take it if Smash 4 has only 12 newcomers and these are them. Well we only got four or five months left of waiting anyway.