It's really not like the Wii U is some super complex machine.
Give any casual Mario Kart Wii or NSMB player a copy of Nintendo Land and they can play it just fine. Probably have a good deal of fun with it too.
Same goes for Mario Kart 8, Mario 3D World is even easier to play than Mario Galaxy, NSMBU, Just Dance, Wii Fit U, Wii Sports Club, etc. etc.
It's not like suddenly Nintendo's games have become hyper complex and gamers are smart enough to not be scared away simply by buttons alone (otherwise things like Nintendogs and Brain Training never would've worked).
The problem Nintendo has is an enthusiasm gap, not an accessibility gap. The Wii U is plenty easy to use and still uses the Wiimote in many of its games (basically any multiplayer game will let you use the Wiimote or even require it).
When playing with casuals I remember hearing that dreaded "you know there's an iPhone mini-game just like this that I got for free" when we were playing some of the games. It's naive to keep saying there's no impact being made here ... consumers, particularly the casual crowd has simply had their eyes opened with far more options today than in 2006 (which is almost *eight* years ago now ... an eternity ago in tech cycles).
I've played the Wii U with some of my friends who don't really like video games but enjoyed the Wii, and they can play the Wii U just fine. They even have a fair bit of fun with it. But none of them want to buy one, not even after playing some Wii Fit mini-games or Wii Sports again. And they actually liked Nintendo Land too, Mario Chase especially.
