You need to stop shitposting in this forum, right? Then stop bounty programs and signature campaigns. This is the main reason for shit posting. If you really want to save the forum, stop signature campaigns .
This is thinking from a retrogressive perspective. Doing what the OP has suggested can only be counter productive. Whether we accept the reality or we live in denial of it that the major thing which has kept this forum bubbling and fast growing is the signature and bounty campaigns. Hardly is there any crypto enthusiast who hasn't read or heard about the bitcointalk.org site. All thanks to the traffic the signature campaign has brought this forum. I believe stopping this will deal this forum a hard blow. But I would like for Theymos to experiment in this.
Maybe it's the quality of the sig campaigns that is the problem, If three quarters of them were banned, then lurkers and other visitors would be less likely to be scammed, and maybe Bitcoin could start to improve its image.
Oh, really that bitcoin could start to improve its image?