What would you do differently if you established WHATWG again and why?

One more thing I would do differently is have a much stronger code of conduct from the start, which doesn't just disallow bad behaviour but actively requires positive interactions. There's no excuse for being cranky on a mailing list. Being obtuse or just unpleasant is not necessary. We had many people over the years who would push right to the limit of what was acceptable, and I wish I had been much, much stricter, stepping in and removing participants as soon as they were even slightly obnoxious. I think we would have made much more rapid progress and grown a much bigger community much quicker if we had done that.