Right now, if you are an editor in WordPress, you can edit any posts and pages. Hence, the administrator of a big group blog would not have many editors ---because the blog posters would not like the idea that their colleagues can edit their posts.
But it would be great to be able to have a great number of editors for some specific pages. That way, any group blog powered by WordPress would be able to tap in the "wisdom of crowds" (see James Surowiecki book by the same name) ---the same way Wikipedia does. For more on Wikipedia, see these two posts:
Collective intelligence (a.k.a. wisdom of crowds) is a mechanism at the heart of Google PageRank, Wikipedia, open-source software, prediction markets, etc. It is very powerful. WordPress could tap into that very easily, by allowing a page-by-page editing role.
The WP admin would set who are the editor(s) of a particular page ---one registered person, two, a bunch of blog authors... or any internet citizens like in Wikipedia.
Thanks a lot for your attention. Contact me for more info, or leave a comment below.