Yeah I know, I keep on making these. But I keep on coming up with different ideas for it (and can't find the old threads).
I am convinced that Nintendo needs to focus on a lower-cost console that's more approachable to most people, kind of how many people bout a Wii alongside the PS3 or Xbox 360, making the Wii the most popular console. While having the most powerful console will always be demanded, I don't think that's an arms race that Nintendo is willing or able to compete in.
To me it seems that Nintendo wants to focus on making scaleable games, where you can pop the cartridge into the NX console and play it at full quality, or pop the game into a handheld and still get a decent experience. Developers would need to make sure their games work with this, so using x86 and catering to port developers would simply not work. The Cafe system is still a pretty efficient system, that we'll have to see how much it can flex.
I don't think the NX console will be more than 3x powerful then the Wii U, as Nintendo will mostly focus on improving anything that developers find limiting at that budget level. I'm guessing a price point of $250 or less, with the only controller being a Pro Controller (or an updated version). That would allow it to play the entire virtual console library (except DS) and can even play Gamecube games if analog (or trackwheel) triggers are used. Many Wii U games support off-screen mode, and so should be patchable to remove gamepad requirement. You can still buy a Gamepad or Wii remotes to play the rest of the games though, but they are not included - or at least not included in the base model.
There should be little to no similarity to the Wii an Wii U, either in style or branding. It caused too much confusion for the Wii U. The sole exception would be if the flexible NX architecture allows the Wii U to be upgraded to support NX games. But that's a level of complexity that I don't have enough information on.
After that, support for an HDD should be built in (either as an internal drive bay or an external attachment like the Xbox 360.