I do agree, this game was a slow burn in every way. You didn't get the first incest penetration until CH8 iirc. it could have been 7. No one has really learned about Hunter yet, but it has to be that way. If Sterling told anyone, the story would have to be changed to then close out the game. You don't have anywhere to go once the good guys find out Hunter is trying to rape them all. You can only stretch him not accomplishing or getting defeated for so long at that point.
So the longer WWG keeps him a secret to the girls, the longer the story has a place to go.
That said, it was still a fun journey. The teasing and build up of the relationships with Sterling only helped when the sex scenes finally happen. It's probably much easy to swallow for someone who plays the game for the first time now, but back in the day having to wait months between chapters wondering if, "Is this the chapter where it happens", was pretty bad lol.