I haven't played a good 3D platformer in twelve years
Go hit up one of the Galaxy games or 3D Land if you want something far more recent. Both are pretty great.
I found 3d Land to be pretty forgettable. Just meh all around.
The Galaxy games are good.
3D Land's biggest problem is that Mario doesn't feel nearly as responsive as he does in the big console releases, it's almost as if the analog stick has lowered sensitivity because of the thumb sticks being crappy and the jumps don't have that nice little bit of weight or that wonderful arc that I like in my Mario games. However, the level design itself actually serves as a better bridge between the old 2D to 3D gameplay and stays much more true to the spirit of the original games than Mario 64 and its sequels ever did; it's worth experiencing.