Actually the games were designed on the Wii so that you don't have to swing the controller in exagerrated motions like you see in the promo videos, although you can, a simple nudge of the controller will also work just as well, so you probably won't get tired at all playing the games (unless the game was designed to give you a workout). Here is a quote from Gamepro magazine:
"We've actually started to play a lot of the Wii recently, especially since developers and publishers are now actively previewing their games, and we have to say all those Nintendo press screen shots are rather deceptive.
Most games won't have you waving the Wii remote around like a mad man. A lot of what we've played has you sitting down on your couch, with your elbows resting on your knees. Another thing to keep in mind is that most games have multiple control schemes. While certain actions require rigorous actions with the Wii remote and Nunchuk, the entire game isn't just one motion, repeat, and serve. From what we've seen and played, the Wii-mote offers a plethora of control options."
I am far more excited with what the Wii has to offer simply because it's different and most of the games on the 360 and PS3 are pretty much "been there, done that" games. But don't take my word for it, here's a vid from IGN.com in 2 parts.
http://www.youtube.com/watch?v=EgLxUBJI ... ed&search=
http://www.youtube.com/watch?v=n1tEX5vT ... ed&search=