It could be a Wii redesign, not an upgrade. Removal of the GC relic the same way DSi removed the GBA one, ability to "plug in" more than one balance board(or other such peripheral) at once, added solid state drive along with the optical one by making it possible to play game off the SD card, WM+ build in Wii remote and wireless nunchuk, maybe a camera or Wii speak or both integrated in the sensor bar. Sell it for 250$ and you get yourself the Wii equivalent of the DSi, it work for handheld why not for console?
Persons without argument hide behind their opinion