If I remember correctly, a character around 1978 was Romana and referred to as a Time Lady. Calling #13 that would sound very archaic but "Lord" is not of thought of as neutral in the way "actor" usually is these days. Then the choice of assistant needs great care, especially if they are solo males: the doctor needs to be the dominant character but we dont want to get into either dominatrix territory or such a weak male assistant they are useless. A rory-amy pair woukd be simpler.

It could certainly work but good writers will be needed to handle a potentially complex relationships.