That would make it more collaborative, that's for certain :-)
For designating authors, the user who initially creates the story would have to specifically name the users allowed to participate. I can't see any other sensible way to handle it. As you point out, letting users add themselves is an open invitation to trolls...
The pre-edit queue may or may not get into scoop 1.x. I've been thinking of entirely rewriting the story publishing process for scoop 2.0, in such a way that adding a "pre-edit queue" or other stages of document workflow would be easy. If the idea excites one of the developers enough, it may get into 1.x though... I have no objection, it just isn't a priority. But anyhow, my early thoughts on it are that a user would only have a limited number of articles in their workspace, say 2-3 (admin set, of course) and couldn't add any more unless they either delete or put into voting an article currently in their workspace. For collaborative articles, the article would take up one space in each of the authors' workspaces.
Discuss the art and craft of writing