Okay I get your points, but just from a usability point of view:
How on earth should a "casual" CoH2 player know why both trenches with the same name have not only different stats (different kinds of cover, that ADDITIONALLY SHARE THE SAME ICON TOO) but differ from how can garisson them?
This is just ridiculously stupid in my point of view as nothing in the game explains these things. You literally have to go to a board like this and ask or check the game files
This is an issue that happens in most games. Having normalised behaviour seems "hard". And this is not the first and only case unfortunately.
Additionally a question from my side: Are trenches worth the time? I can't remind building a single one of them in my whole time on CoH2.
I guess you are talking about Axis ones. Yes, if you have the time.
OH: before, it was the only possible way of creating green cover (now Pios have sandbags). Still, it's makes dislodging Osstruppen annoying (defensive doctrine sucks unfortunately)
OKW: it's been a long time since i've seen Luftwaffe. I'll put MG/Raks inside for the extra protection.
Note: you can always use trenches as infiltration spawn points. I've use it to spawn commandos/Falls, and most people don't expect it.