IIIIITHE1IIIII on 18 August 2012
My guess would be that just like Mario Kart 7, the game is rushed (in fact, I think I heard somewhere that all maps were designed through an extremely limited amount of time).
That's very different compared to how Miyamoto played through Super Mario 64, realized it got boring after a while, and remade major parts of the game. There's simply not time for enough quality-checks.
