I think there are a few options for saving it, and NX is one of them... depending on what it is. One of the following things could work:
1-The Monster Hunter option. IE, Nintendo needs to draw in major Japanese third party content. To clarify further, if you look at the gen on gen handheld market in Japan, 3DS did moderately good in comparison to DS, but at the expense of Vita. Monster Hunter switching platforms killed the Playstation handheld market but kept the Nintendo ecosystem vibrant. If NX - whatever it is - were to be host to other titles like Metal Gear, Final Fantasy or Dragon Quest... or better yet all of the above... in addition to the Nintendo games that are popular there, it could be a solid hit and perhaps become a bit of a craze that could even grow the industry back a bit.
2-The Fusion option. The popularity of the mobile market is clear. If Nintendo links its handheld and home console systems, this could present an extra attractive gaming option.
3-The NXablet option. If you can't beat 'em, join 'em. NX could be a dedicated gaming mobile device, like a phone or tablet with physical buttons and controls, one that plays apps and also classic-style games. This could potentially be a home run if done right.
4-The "Wii" option. Something new, unexpected and exciting. This option always works. Mobile is the craze right now, but if something new and fresh that can't be repeated on mobile is offered, people will jump all over it like they did their Wiis.
Ideally the solution to the problem is a combo of some of the above, such as #1 and #4. A major flaw of Wii was it offered a great experience and fresh concept, but didn't offer the classic content to hold traditional gamers beyond the generation. Any new device should try to do both.
