Name: Nintendo X1 or Swap (Names by RealSpinningSonic.)
Features: TV and Controller Screens (Origin: Wii U)
"On The Go" - Like the Switch, it can be played on the go as long as the controller is charged. (Origin: Switch.) Can go plenty of distance away from the console.
This also means you can play without the console on. This could be expensive though, so if it ever becomes real, I wouldn't count on it being "double-system" or whatever.
Touchscreen/Stylus Support - Of course.
Backward Compatibility - Can play Switch, Wii U, and Wii games and is compatible with past controllers sans the Wii U Gamepad. Also, the return of VIRTUAL CONSOLE!
Service Reboot - Miiverse would come back, hopefully on all consoles that used it including the Wii U.
Motion Control - Of course.
Plenty of Launch Games.
Music on Applications (Origin: The Wii and Wii U/3DS eras.)
Comment more features below!