They should be able to make something considerably more powerful than a PS4 this year or next year though. You don't need to wait until 2018.
AMD has 14nm/16nm Arctic Islands GPUs coming this year that will blow the PS4's GPU out of the water.
I'd say release a 3TFLOP-range high end console this fall and start building that userbase quick (having Zelda, Splatoon 2, and Mario 3D in the first 6-8 months will be critical).
Then in 2018 release a 4K NX model.
NX is a platform, it's no single console or portable. Nintendo games just scale up and down, third parties have the choice (games can work on specific models depending on hardware need or all them if they want).
Why adhere to "rules" if they only benefit Sony/MS. Change the rules, it's 2016, you don't have to keep making hardware like it's 1989 forever.
