Correct about editor privileges to freely mark messages as members of any node. Authors won't.

Actually, these categories of author and editor are kind of arbitrary, artifacts of WordPress. We can already see how they're too coarse-grained for this environment. That access-control system project (now #2 in the takeoff queue) is intended to make it very fine-grained. The idea is to be able to specify whether or not a member is allowed to perform particular tasks at each node. The ability to change the checkboxes for your own posts is one discrete privilege, the ability to change it on others' posts is a separate power.

So those titles will be phased out in favor a system more like DamnTikiWiki's, which shouldn't be held against it. Assigning privileges to groups and putting users in the groups is a solid standard practice.

(I just handled a phone call from the client about this very subject. The whole world wants me to get it fixed ASAP. I can tell when the universe is trying to give me a hint.)