So I'd prefer the addition of some sort of barrier to entry. Either an invite system like the private file-stealing sites use, a sign-up fee like Metafilter uses, or a vetting process for potential members.
Ideally, I'd love to see Paul Graham take a couple hundred of the best users and start a new forum. After they had some time to establish the community, people like me could apply for membership, which would involve submitting a written case, and waiting a week for the existing members to vote on it.
*This was originally a reply to lionhearted, who deleted his perfectly reasonable post.
There's a well-research phenomenon that people believe that a group is more valuable if it was harder for them to become a member. It pops up everywhere from YC to skull & bones to young men being ritually injured in the deserts of central Australia.