Yeah unique characters definitely deserve more uniqueness. I think the current baseline is quite alright for the nameless npcs.Keep in mind that quick sex is something Inno hacked together like two weeks ago while procrastinating on writing quest dialogue, it should account for most constraints on normal sex scenes eventually.
But yeah, I like the overall system too. What would help a lot already would be character specific dirty talk/commentary or maybe more options with a couple paragraphs of intro text that make you start in non-default positions, like Vanessa's scenes.
One thing I don't really understand is why sometimes your companion can join in and sometimes it can't, I'd kinda like the option for companion involvement to always be there, instead of this greyed out "can't have sex infront of y" thing. Also it's very pie-in-the-sky but race specific banter would be neat.