Not to mention the problems it would it would bring up with regard to commanding officer-subordinate relations. I suppose on some shows it might be just the thing for more possible plot angles, but I think in ST it would have been a distraction that would have gotten in the way of the main plots.
TNG did a pretty good episode of that. Lessons
I guess we just weren’t ready for that in the 23rd and a Half Century.
I think that was the case in most 60’s television. How many episodes did Ponderosa Wives last? Even Ben’s were done in a flashback. 
Spectre of the Gun? While low on plot perhaps, it was nicely shot, the close ups, the set which set the ethereal nature of the Melkosians etc, a nice break to the so called turd season 
Hey there, BTES, by any chance did you ever watch Trek in the Blake Hall TV lounge, weekday afternoons? Those were simple times! There was only one Trek, and even now there is only one Trek ying on DVD:TOS. I do enjoy the later series very much, but they don’t hit me in the gut the way TOS does.
(For everyone else, we both went to USCD at least somewhat concurrently, though I for one have not been able to make the connection to anyone I actually remember.)