Definitely the gimmicks. Motion control was almost completely a flop (in terms of what it brought to gameplay) and was downright annoying. The only game I really enjoyed it, and felt like it was worthwhile was Skyward Sword, but even there I got killed a few times (those Beamos) because of how it wasn't responding properly.
With the Wii U, I mostly play games with the Pro Controller. However, I will say at least they gave us options, much better options than on the Wii.
With the Wii U, I mostly play games with the Pro Controller. However, I will say at least they gave us options, much better options than on the Wii.