The relationship isnt that strange tbh, pretty much every regular 3D Zelda since OoT 64 has been good for +500k sales. The only real mistep was Skyward Sword because gamers had already given up the Wii and the Motion gameplay alienated interest for many core fans.
The core 3D Zelda fanbase was/is around 500k. Lets see if they can reach these numbers on WiiU - it might be possible if the game really delivers.
I'm not certain there really is a 3D Zelda vs 2D Zelda thing anymore. I suspect given that Zelda is an adventure series driven by puzzle/exploration/narrative, it doesn't make a huge difference for the fans whether the gameplay is full 3D or top down 2D.
I mean if we look at the last ten years of 2D Zelda, what do we have? 200k+ for Minish Cap, 900k+ for Phantom Hourglass, 700k+ for Spirit Tracks, 400k+ for ALBW. It's all over the place.
The last ten years of 3D Zelda? 500k+ for TP, 500k+ for OoT3D, 300k+ for Skyward Sword, 40k+ for WW HD, and now a 200k+ opening for MM3D.
I'm not sure we can really project much about 3D or 2D Zelda from these numbers. In the last ten years, we've definitely seen 2D Zeldas sell better overall in Japan, but I think considering the 200k+ opening ALBW had, the legs were pretty disappointing. We'll see if MM3D fairs any better on that regard. In the end though, I don't think it would translate much to success on WiiU, given the disparity in userbase. No one was interested in the WW HD release, but yet people are all over OoT and MM on 3DS.
Ninty should quickly ask Kachou Arino to promote this game asap lol.
For the legs, I believe this will had better than LBW with nostalgia power,the fact that this game is highly popular in hardcore circle and it is released in 3ds barren period, I believe MM sales will maybe achieved 500k?