If it becomes the norm in a way that all games can only be played with it, it either has to become better or gaming wouldn't be that much fun to me as it was earlier.
This was also my fear before the wii was released, but thanks to Zelda, I understood that the Wiimote/Nunchuk combination can be used like a traditional controller.
It is important to see that the motion control is not THE new way of controlling, but an alternative way. For some games, it gives you an entirely new and better feeling. For some games, it is a slight improvement, but you could live without it. And for some games, it's completely worthless. It'll probably take some time until developers understand that; it was exactly the same with the DS. But when the novelty of motion controls wears off, there will be great games for the Wii without any motion controls.







