The thing is that if we think of it as a handheld the rumoured specs are fantastic, much better than we could hope for from Nintendo. 14nm Pascal tegra? It doesnt get any better than that for a portable gaming device.
Having played NSMB2, Hyrule Warriors Legends, Super Mario 3D Land, Smash 3DS, Monhun 4U and Generations, Mario Kart 7 etc. along with all of their Wii U counterparts, I'm convinced that this is the best way forward.
I rarely play games on a big screen nowadays. The handheld convenience is way too strong even inside the home (Wii U gets a ton of playtime because of this). When I play on a big screen, it's on my PC because nothing else can compete and nothing else will ever be able to compete.
While the freedom of the Wii U gamepad in the home is glorious, you eventually run into range issues or even the bother of not being able to just take the thing with you, which is where the 3DS steals quite a bit of playtime for me, even for games that I have on Wii U.
If NX is what we've been told it is, then it's like it was made specifically for me.