•Discourage/ban Open threads. They are an unusual thing to have on a an open forum. They might have made sense when posting volume was higher, but right now they further obfuscate valuable content.

I don't think this is a practical idea. The site is hostile enough to new users who lack much rationality knowledge and perspective on the content. The Open threads (and even moreso the Stupid Question threads) give people a place to pose questions and try out ideas that they aren't confident enough in to make into Discussion posts. People are less harsh in those threads (although I've seen people be harsh in stupid questions threads) and it provides a chance to participate in content without having read the 1700 pages of The Sequences or having lurked on the site for 2+ years.