After playing Wii Tennis, I have to agree with Matt. And it's the exact problem I had with Wii Tennis: it's too simple. When the novelty of the controller wears off (and it does), you realize that Nintendo removed everything that would give the game even a little edge.
And no, wrist flicks aren't just what people do to cheat, for a lot of games wrist flicks actually work better than if you actually performed the real life action, and thats a fault with the design, not the player. I play Tennis, and the first thing I did when I played Wii Tennis was try to swing at the ball the way you would if you were actually playing Tennis, and it didn't work. If the wiimote picked up my action at all it was horribly timed. The game didn't start working properly until I reduced my movements to wrist flicks. And with nothing else to do in the game but flick your wrists, when the novelty wears off, you're just kind of standing there, flicking your wrists...and that's Wii Tennis.
I don't think the fact that WiiSports is nothing but a collection of demos would have been a big deal if Nintendo had been honest about that. But they're treating it like a full-fledged game, and pricing it that way, too.