Personally, I am also quite skeptical of the benefits of these approaches. I would like a web more focused on documents, but many of the "forbidden" features these communities define are actually things I was excited about when they were introduced and still would not want to miss on the web. At the same time, just limiting the technology will not make it magically better.
I would love to see more experimentation towards more hypertext and the things it could offer to the user, but just using a subset of old technology seem not really like a great way forward.
At the same time, why can having a cleaner, more performant web not be a social movement amongst developers? I still remember when many of our websites features "Valid XHTML" or "Made with Web Standards" Badges, to show our peers and the world what was important to us. Maybe setting some rough guidelines what we envision a modern, performant and user respecting web to be and whipping up a few badges to show our colors could get as further then trying to reinvent the technology from scratch?