Indeed - quite a lot of stations already have platform staff for checking doors and notifying the driver that it's OK to close. I suppose it would depend on the ratio of active trains to stations as it which is most efficient. I believe TfL have committed to manning all stations after the closure of ticket offices so having platform dispatch staff may be a useful use of labour.

Vancouver's Canada Line (fully automated) opens the doors fully and then tries to slowly close them if it detects an obstruction. A similar system could be in place.