I think that reviewers should base there reviews on whether or not they enjoyed the game and why, so that people reading them will have an idea of whether or not people will like them. If you only allowed people who like the wii mote to review games, then you would only have people who love the wii and might be biased in the other direction.
And what about the biggest (non wii fit game) out right now? SSBB was not even designed for the motion controlled and i know people who bought the system for that game alone. The motion controls that they through in are very sixaxis like (shotty) and most 3rd party wii games have really bad motion controls.
Anyway, reviewers should be able to be honest and share what they think, not be held to some kind of restriction.







