Have you ever played the Wii? You only get tired if you play for hours while gripping the controls and not letting go, and over doing the motions. I know from experience (Metroid Prime 3 and Wii Sports) and if you get tired, go take a break.Wii, I imagine will be VERY exhausting and annoying, stick with the tested format.
I'm getting this for the Wii. It looks so much fun. You get to do the taunts with the Wiimote, you actually get to finish the moves yourself, it is a different game, and it looks like it will be very fun.
Can't wait for the big news.