Quoted from mystman12:

One big problem I just realized the current rating system has is people can rate games after playing them a few times at an arcade. Many review comments make it very clear that that they've probably played the game for less than hour total in their lifetime, but didn't enjoy it that much so it *must* be bad even though they haven't even taken the time to learn the rules, or maybe the example they played was just in poor shape.
When writing a review, users should be required to input am estimate of how many hours they've spent playing the game, and that stat should be shown alongside their review just like how they show whether or not the reviewer owns or owned the game. That stat could then be used to determine how much their review affects the overall score of the game.