Sending just a stereo mix can be a bad idea depending on the director. Mainly to make sure that start time is correct (a few frames of can screw up a whole cue). Also, when you have lots of dialog the relative volumen is very important and if not set right can get you unnecessary revisions.
I think i’s better to send both videos and stereo mixes unless you really trust the director (and he trusts you as well!).