If you think about it, we're halfway through the game and not only just 2 out of the 4 girls are (barely) having sex, Lily was basically completly ignored during these 8 Updates, and i wouldn't even say that it's because the build-up was TOO slow, it's more like there are waaay too many girls that needs attention, i feel like that's another reason for why HC2 feels really slow for most people, it's because THERE ARE 5 GIRLS whose corruption is happening at the same time, you gotta do 4 quests (Aywin&Celis is 1 quest, and then 1 for each of the 3 side girls) just to see everyone get corrupted just a little bit. With HC3 it's better cause there's "only" 4, but with all the extra characters added, having one less side character makes no difference at all.
I really hope HC4 will go back to how HC1 was done and we're only gonna get 3 girls, either 1 main and 2 side girl, or 2 main and 1 side girl, honestly i wouldn't even mind if it was just 2.