I wouldn't go by NSMBU. The levels were focused on more than character design there. Either wait for Smash Bros or the next 3D Mario game. --- Currently Playing: Shenmue2, NSMB2 http://youtu.be/X21mJh6j9i4
Can't really say until we get either a mainstream Mario adventure game or Smash bros. we won't be able to see any good detail in his appearance god what if they gave his overalls that stitching detail they had in melee and brawl for Mario and Luigi.
The NSMB series has never really been much for pushing the graphics of a system. 3D Mario on the Wii U will make NSMBU look like crap in comparison, the same way SM64DS looked in comparison to NSMB, Super Mario Galaxy in comparison to NSMBWii, and SM3DL in comparison to NSMB2. --- I've decided not to have a signature.