Even the power door fitted MK3 stock can only operate with modified power cars - I don't think anybody is expecting a guard to have to identify that the train is correctly stopped at platforms on anything other than charter tours, unless I'm missing something. Can you give an example of a regular passenger service where the doors are not opened or released by the driver at present?
I can only speak for the North but the following classes have complete guard control where the guard releases and locks the doors at Merseyrail, Northern and TPE:
142, 143, 144, 150, 153, 155, 156, 158, 185, 319, 321, 322, 333, 350, 507, 508.
Probably plenty more about across the country