The "NX" won't be announced until at least next year, Nintendo already said that, so It probably won't be released until 2017 at the earliest.
It doesn't matter if the Wii U has potential, it hasn't sold very well, and it's not viewed as a "current gen" console by most people, more like the equal to the 360 C or the PS3 slim. I know it's not, and that it's capable of more than most people know, but it doesn't matter at this point since it can't out do the One or the PS4.
On the other hand, they probably can't get a better opportunity to get ahead. Since now that they know very well what the One and the PS4 are capable of, they have a huge chance to develop a console that is more powerful, as Microsoft and Sony aren't going to be able to oppose it with better tech, since their console foundation for the next 10ish years has already been set.
And while they work on the hardware, they can live off of their 3DS and Wii U game sales, along with their new mobile branch.
Lastly, they've been working on a Gold/Plus equivalent for that past few years, and I assume they are going to announce it soon. If they lay the ground rules and such out right, and don't do anything that would be frowned upon by the public (Xbox DRM, PS4 HDCP, etc), then they could easily get back into the console race, and possibly out do Microsoft and Sony, since games have never been an issue for Nintendo.
tl;dr ~ Nintendo is making a good move by moving on and not trying to fix with the past.