It seems to me that wouldn't help that much. Just because a rating was made a year after a game came out doesn't mean the rater has multiple plays on the game--it could still be just one, or even none (stupid, but it does happen). It's much more useful if the rater indicates an approximate number of plays in the comments.
I see what you are saying but that still doesn't tackle the real concern for me here which at its heart is this:
A lot of people (me included occasionally) rate once and never look back. I would love to see more recent ratings and re-ratings rise to the surface if I ask for them. Caylus is one example. Come July, I would like to see if there is a pattern among the ratings that have been there 6 months and those that are brand new. Also, the more re-rating a game has is telling as well.
But mostly I think a voluntary reminder that my rating hasn't been updated in a year would be fun and would keep information current.