I'm starting to suspect there's something unusual going on involving 3D World. Maybe COMG is having trouble getting orders of the game because they're a small chain or something? It makes more sense than a Mario platformer being a flop in Japan.
I've seen it mentioned in this thread once already, but maybe people just aren't interested in pre-ordering it because they know there will be tonnes of stock when it launches. We've seen the majority of Nintendo-published titles on Wii-U have shipped far more than they've sold FW.