Nintendo denied the hybrid idea though. The stronger rumors, including the one from the Wall Street Journal, suggest that it'll be two separate "NX" units, console and handheld, not just a handheld docking into a tv. The question is just how close those two "units" will be as far as hardware and compatibility goes.
If those two different units are actually really a single system though (so, they're different hardware, but compatible with each other, not just some behind the scenes "easy to port" stuff), and the "NX" brand is not just a marketing term, then the console version can't be that powerful. It probably would be designed for higher resolution versions of the handheld games, which still will leave it behind the PS4 and One, even if the portable is a big jump over the 3ds.
I still think that's their best option. A PS4+ thing from Nintendo at this point would be a system with no audience at all since they wouldn't be able to give any consistent software support to it - and it'd also hurt their future portable at the same time. A portable/console shared library could be carried effectively by Nintendo by themselves alongside some Japanese support. It probably won't get them the sales of the PS4, but it should at least perform better than the Wii U currently does.