Eurogamer: Nintendo NX is a portable console with detachable controllers (It also connects to your TV, and runs cartridges)

[Wyrdness]

TheSpindler said:

Well this guys said he got it from a Japanese guy who said he would release the info two months later.  I think some of their info is correct, but how much I'm not sure.  I think the device itself has probably far more to it than what people currently belive now and that its gimmick is simply a screen controller you can carry as a handheld with a dock.

LCGeek mentioned that the networking Nintendo has been working on, the streaming tech stuff, has been expanded upon.  It could be that's the reason the controller is detachable.  Maybe the 'dock' device can stream to multiple devices, maybe there are multiple SKUs about with different screens, maybe they can stream to normal tablets or phones?  No idea really.

But it could be why Nintendo was afraid of it being copied.  

Makes more sense than what this rumour is peddling tbh and it falls more in line with some of the patents especially the one that mentions devices of different specs communicating.

A screen controller that is also a stand alone handheld is plausible afterall the 3DS can be used as a controller for Smash just fine.