I said this in another Wii U thread, but a shorter version:
Personally I would conjecture that the real problem is 'more evolved' motion controls are not practical or inexpensive yet. There's a real problem with how to track a control device in a full three dimensions, precisely, without using a ring of sensor bars around the device in the room. Move has more tech in it than the wiimote, yet is still inferior in terms of reliability and precision - it loses calibration and drifts constantly. The Wii uses a very simple (braindead simple) hard lock-on system: two LED dots over the monitor that provide absolute triangulation for the control device.
The problem is, I don't know if improved motion controls would have been feasible yet with Wii U; at most a few extra sensors ala Move, but it basically would have been a Wii Motion Plus device. No significant upgrade.
I would not be surprised at all to see Nintendo turn back to expanding motion controls again in the future. But for now, it seems really hard for people to actually take one thing Nintendo said at face value... that Wii U (from their perspective at least) is designed to fuse the Wii to a 'core' game system. Which is literally what it is. wiimote+ combined with a conventional game controller as a primary input device, not a dongled accessory. With all the industry standard buttons on it (clickable sticks even). The screen pad idea, which a lot of people can't seem to wrap their heads around, seems pretty obvious to me considering the kind of interface options it opens up that mirror a lot of what's popular right now.
Sure, we can see in 2 years where things stand. But predictions don't work in the game industry anyway, in general. Just about nobody was 'correct' this generation no matter how wild, or how conservative, how 'obvious' their predictions where.