Well, if I remember correctly, Peach wasn't in NSMB Wii as playable because of skirt animations being difficult to create (I know that was a joke), but still, with the way Nintendo is sometimes, it wouldn't surprise me if that were kinda like a half-joke... kinda like when someone says something seriously, but if they get called out on it they can quickly fall back and go, "no no no no lolllll that was a joke. We're just playin."
Point being, Nintendo would prolly think it'd be too hard to do textures on Mario's overalls for a platformer or whatever. However, I would really love to see that, as well as a revamp of environments being less bright, and more bump-mappy. Good example is Space Junk Galaxy when you're on the rocketship. It's all texture-y and has that awesome sheen. Also, King Kaliente (or however you spell it). The cooled, black lava around the lava pit has that awesome lighting to it. Oh yeah, can't forget the fuzz on the bees and some of the enemies in Mario Galaxy.
If you remember in the trailers for Galaxy 2, quiiiite a bit of the grass had the "fuzz" effect on it, but then when the game came out, it went back to the solid, blocky look. Examples below.
