This is true.
But I still can't understand why a number is more clear than a letter.
PS3 and PS4 have the same difference than Wii and WiiU to me :\
PS: I don't like the WIi U name, just to clarify.
As someone pointed out in a post a long time ago
http://www.neogaf.com/forum/showpost.php?p=74079668&postcount=1671
The problem is that everything for the Wii had "Wii" in the name, so Wii U just sounds like another accessory.
Wii Wheel
Wii Remote
Wii Sports
Wii Fit
Wii Play
Wii Sports Resort
Wii Balance Board
Wii U
Wii Remote
Wii Fit +
Wii Play Motion