Reggie Fils-Aimé explains how Nintendo will not repeat Wii U mistakes for the NX
Furthermore, Fils-Aimé goes on to say how the NX needs to have a "continuous beat" of games for the system, which would create the urge to motivate "more and more people to pick up the hardware."
"We always do our breakdown of what worked, what didn’t, and certainly we’ve done that with Wii U, and we continue to believe that the innovation of the second screen was a worthwhile concept...... when we launch the NX—we have to do a better job communicating the positioning for the product. We have to do a better job helping people to understand its uniqueness and what that means for the game playing experience." ~ Reggie Fils-Aimé
The NX is still yet to be unveiled by Nintendo, however it is said to be a home-console/portable with datachable controllers.
Source (main interview with Reggie himself)