Sorry for the late response; I wasn't on my computer much yesterday.
I am actually against this proposition for a few reasons.
As active GoF members, many of us are aware of who tends to post more in the Party Room and who tends to post more elsewhere. This can be made obvious by simply clicking around the party room for a few minutes.
To me this sounds like a way to track the number of 'useful' posts, which I think is a little bit disrespectful, considering this is a casual forum for people to come to for relaxation, to unwind, etc. Calling one's person's way to relax "not worthy of counting as a real post" because they're playing a game rather than posting in a topic that tends to encourage discussion, especially when it's just as easy to have a meaningless post elsewhere than in the party room, seems to be rather biased against the members who participate in party games.
It also takes 'credit' away from those members who honestly come up with good posts in the Party Room, such as a new popular game or someone who helps to explain the rules of a game.
Since we have no way of measuring the 'quality' of a post until it's read (and even then, as long as it follows the rules of the game, it can be justified as an acceptable post), I just don't think it's reasonable to assume that all posts in the party room aren't even worth counting.