Some time ago, there was a project called Citizendium that aimed for quality over quantity, with articles written and peer-reviewed by subject matter experts who had to use their real names and working email addresses, among other requirements. I always thought that was interesting, since the main critique of Wikipedia is its open editing model.

Citizendium is still around, though they've loosened some of the requirements in order to encourage more contributions, which seems self-defeating to me. I think they should have tried to cooperate with Wikipedia instead. The edits and opinions of subject matter experts could be a special layer on top of existing Wikipedia articles. Maybe there could be a link for various experts with highlights of sections they have peer-reviewed and a diff of what they would change about the article if those changes haven't been accepted. There could also be labels for how much expert consensus and trust there is on a given snapshot of an article or how frozen the article should be based on consensus and evidence provided by the experts. This would help users delineate whether an article contains a lot of common knowledge or whether it's more speculative or controversial.