Hmm, I just boguht a wii this past wednesday. Only had enough scratch to get Zelda, and I don't know where the guy was going with the "tired arm" thing.
Now I don't know about him, but when I play, I just rest my right arm on my right leg and gently move the pointer. It's extremely sensitive, and only requires very tiny motions to move a large distance. I suppose 12 years of playing FPS games has taught me to expect that, but, well, maybe the journalist didn't play them in college.
The only time I actually raise my arm is to swing or aim, and even then, not much. and if raising your arm tires you out, there are other problems you should be worrying about. Like chicken fat and what it can do to the ateries.