I've addressed the feedback I got in Zurich.
https://www.mediawiki.org/wiki/Performance_guidelines
I think this page is ready to have the {{draft}} tag removed. I believe it now represents our consensus on what MediaWiki core, extensions, and gadgets developers should do to preserve high performance. On May 23, I'd like to move forward with making a tutorial and a poster based on this. So, please edit, speak up, and so on, within the next week.