I agree with most of this, except I'm a little skeptical of the claims in the "More bodies means better articles" section, such as "featured articles are so good precisely because they are edited by so many". Many featured articles are good precisely, to the contrary, because a small number of people did the library research to write a good article. This doesn't necessarily have a 1:1 correspondence with the views discussed in the article: When a history article includes coverage of 4 major historiographical views on a controversial subject, often all four of them were added and summarized by the same editor who is describing the debate, not by separate editors each representing one of the viewpoints.
That does seem to vary by area. The featured articles on major recent news subjects may be closer to fully crowdsourced, piecing together hundreds of sources, mostly newspapers/magazines and mostly available online. The good history articles tend to be more often written by smaller numbers of historians or history enthusiasts who have read and can cite proper books and journal articles on the subject. For example, one user I've run across is single-handledly responsible for hundreds of lengthy articles on classical antiquity, with >80% of the content and >95% of the references in each typically being hers: http://en.wikipedia.org/wiki/User:Cynwolfe
I think more and more diverse editors could have many positive benefits, but I think quality is more important than quantity. Some areas have very good editors. Mathematics comes to mind as probably the best in terms of having editors who are very knowledgeable in the field and also interested in writing Wikipedia articles; I was tickled to find out that mathematician David Eppstein is a prolific Wikipedian, among others. But some areas lack much in the way of editors who are knowledgeable in a subject and willing to do the library research needed to produce well-cited articles. Those areas could be greatly improved if they had the analog of folks like Eppstein (or Cynwolfe) writing articles.
That does seem to vary by area. The featured articles on major recent news subjects may be closer to fully crowdsourced, piecing together hundreds of sources, mostly newspapers/magazines and mostly available online. The good history articles tend to be more often written by smaller numbers of historians or history enthusiasts who have read and can cite proper books and journal articles on the subject. For example, one user I've run across is single-handledly responsible for hundreds of lengthy articles on classical antiquity, with >80% of the content and >95% of the references in each typically being hers: http://en.wikipedia.org/wiki/User:Cynwolfe
I think more and more diverse editors could have many positive benefits, but I think quality is more important than quantity. Some areas have very good editors. Mathematics comes to mind as probably the best in terms of having editors who are very knowledgeable in the field and also interested in writing Wikipedia articles; I was tickled to find out that mathematician David Eppstein is a prolific Wikipedian, among others. But some areas lack much in the way of editors who are knowledgeable in a subject and willing to do the library research needed to produce well-cited articles. Those areas could be greatly improved if they had the analog of folks like Eppstein (or Cynwolfe) writing articles.