I am considering implementing a flagging system to deal with this issue. Rather than relying on user ratings which, when used to form an aggregrate score, might not express directly that a pressing change to the article is needed, or if something has already fixed, it would not be clear from the existing ratings alone.
Instead, if an article is vague, empty, or otherwise incomplete, users and moderators can just say so, and it will flag the article similar to how Template:Stub or Template:NeedsReferences have been traditionally used by editors. I think moving this flagging to a core feature and possibly allowing non-editors access to it (with a permission of course), can make it more useful and would be easier from a development standpoint to determine when is an appropriate time to send notifications to editors/authors.