So what, they will have 3 consoles on the market? WiiU, 3DS and NX?
NX is replacing something.
NX is "brand new concept" therefor mayby not.. mayby this is a dedicated gaming phone or some kind of VR system.
We don't know.. but a 2016 replacment for WiiU.. would be the thing that make the less sense.. IF it should replace anything.. it would most lickly be 3DS.