Mediawiki, the software behind Wikipedia, already has all those features, includeming the possibility of moderation by privileged users or automatic updates, on a per-page basis. You'd just need to use the software for blog content rather than encyclopedic content.
I'm asking you about the details that make them different, and which you consider relevant for a "web with user contributions" in the way you described.
The difference is that those features would be implemented differently in a blogging context. I think that they're things that would improve a collaboration on blog to move from simply getting feedback from users as comments for the author to use to actually collaborating on something to make it better. I haven't thought about what those implementation differences would be; it'd be a lot of work.
Mediawiki, the software behind Wikipedia, already has all those features, includeming the possibility of moderation by privileged users or automatic updates, on a per-page basis. You'd just need to use the software for blog content rather than encyclopedic content.