It has to come out next year. They cant ride the Wii U into 2017, maybe they could with the 3DS.
The fact that the rumour suggest they intend to ship 10 million plus next year indicates to me that it could be both the handheld and home console NX.
I agree with Liger, if it is out next year then do a PS4 and reveal a bunch of stuff earlier in the year and come E3 blow it all out.