Allow deny/revoke privs to apply to roles. Since the current system has "grant" based roles implicitly there is no way to do this now without explicitly specifying each resource (db/collection) ahead of time.
We have a situation where our code creates and drops DBs regularly to hold temp data. In order to do this the application role must get a high level of permissions. We would like however to be able to prevent the application from dropping the core DB that is our data store. Would like to have ability to give permissions on `all DBs except ...`