I just don't think the system is taking off with casuals/non-gamers like the Wii did in 2006.
The new controller is bulky and intimidating with a ton of buttons. It takes gaming back to sitting on the couch (even for most of Nintendo Land).
I have a lot of friends who were going crazy over the Wii in 2006, and I'm pretty much the only one with a Wii U, whereas with the Wii, I had 5-6 friends out there trying to find one shortly after launch.
Wii U just doesn't have much buzz. Especially with women.
It's a product that appeals primarily to core Nintendo fans.
It will have a rough 2013 until probably the second half of this year where they will predictably attempt a turn-around ala the 3DS (price cut + 3D Mario + maybe Mario Kart).