The Matron function could indeed use a bit of improvement, such as taking a girl off the job not just when they're tired, but whenever their status goes "red" in the Girl Management menu, due to low health/happiness, for example.
In addition, perhaps the Matron could serve as a mentor/teacher of sorts, by giving points to all girls in the brothel in whatever stat(s) the Matron's best in? Or if "all" the girls is too much, perhaps a number of random girls each turn?
IIRC Matrons were usually experienced whores themselves, so it would make sense that she has some tips and advice to hand out.