This mode/command will need to support situations where unique indexes restraints must be loosened like during initial-sync/recovery mode.
Depending on the state of the data, and the contents of the oplog, in a backup taken with "mongodump --oplog", attempting to restore the data may cause temporary unique-index violations. The violations will be resolved by the time "mongorestore" has replayed the dumped oplog, but it's currently impossible to do the mongorestore because the unique-index violations will abort the restore.
We need a way to suspend unique-index constraints while restoring a dump with an oplog, then re-enable the constraints at the end of the restore. There should be a rigorous strategy in place for dealing with unique-index violations that remain at the end of the restore.