I would not like to see a rating drop just because a player is not playing that game anymore - why should they be pentelized for things like no internet access for long periods of time, but would like to come back and play later down the road.

What I would like to see is possible after 2-3 mounts without a finished game of a game type, that their rating is simply "hidden" from the Ratings page. That way if they do come back and play again, they can simple start where they left off and their "hidden" rating will become visable again.