Just watching the Media Create/Famitsu sales threads the last few weeks, man is Nintendo taking it on the chin in Japan.
Wii U is a complete disaster there, now after Smash, Mario Kart 8, Kirby, and Mario Party baseline sales are still abysmal, this is easily going to be their worst selling console ever in Japan.
3DS sales are holding OK, but starting to show slippage, and I'm just not sure how many more hardware revisions and how many more Pokemon/Mon Hun/Yokai Watch games can be thrown out before you're simply just selling to the same people who already have the system. I suspect in a year from now we're looking at a 3DS baseline of around 24-28k/week or so.
I really don't think they can wait for 2017 for NX, especially in Japan. It's not like Wii U is really doing great in North America or Europe either, but Japan is a total mess, and 3DS can't carry on like this for another 2 years either IMO unless they want to hand the entire Japanese market to Sony.
Whatever NX is, whether its a handheld or a fusion multi-format series of devices or whatever ... Japan desperately needs some (real) new Nintendo hardware.