I have made a suggestion about this before, but I think I'll revamp it to say that a post should not be displayed on the main page if its been there for more than a certain amount of time lets say a week, or it recieves more than 40 replies this time.
Id like to see the main page change now and then, but the same stuff stays up there for weeks at a time, for instance the rpc/dcom exploit is 3 weeks old at the moment. Hopefully you see what im getting at.