That's true.
For example the MC could have gone on more dates with Jessica and maybe taken her home with him for the night, as he suggested a while ago to her after they had enjoyed each other on the Cape Vedra's beach. (A suggestion she didn't accept.) The group sex in the game now is too random, without much of a build up beforehand, for such lewd scenes to be really erotic; it's just too frenzied, hurried and happens out of the blue for it to be satisfying, with next to no emotional interaction betwen the MC and girls before, during or after. I suppose the idea of the group scenes is if you have N girls involved you get 2N boobs, N vaginas and N assholes and so end up with a sexy scene N-times more stimulating than with one girl, but it really doesn't work like for me and most times ends up much less pleasing than a longer more detailed scene involving one girl would have been. (Henry and Jessica going on a date and then spending the night together at his home would have been much more enjoyable, as far as I am concerned, than a feverish black magically driven sixsome in a cave.) The "talk dirty to me" language used in the dialogues during lewd scenes most times sucks too as far as I am concerned, making the actors look hopelssly crude, dumb, retarded or even deranged at worst!
Erotic drama needs chemistry, magnetism and electricity going on, flowing between and being exchanged by the characters; without striking such sparks like that it become just a case of forgetably butting uglies which isn't nearly as good IMHO.