It would be really helpful for workflow if we had some handy dandy widget that allowed admins to gather feedback on posts in some fashion. (Think about the typical Word workflow, where you send something out and then people add comments, make changes - which are tracked - etc.) Something like this would be really handy, especially for our clients (like Regional San) who have an internal approval process for lots of people who won't have log in credentials for their site(s).
Yes, it would be great if we had a "Solicit feedback" command on the flyout where one could just type in e-mail addresses and it would send to them for review, regardless of whether or not they had user access to the site (because no one wants to stop and go make user accounts right when they're trying to get feedback).
If it could launch some sort of real-time commenting interface like Google docs that would be cool. I can imagine some kind of tool where it would show the latest revision and let a real-time commenting frenzy take place ALA track changes, but none of it saved, only stored for viewing by the primary editor.
I would love to explore this with clients (CalSTRS, Regional San and CHA come immediately to mind) before heading down any particular path. :)