I've been pushing the game a bit to see what breaks, and I found a couple things that might need some looking into;
1) timers keep going down even when the in-game clock freezes at "night-time" at the end of the day, ended up in a bit of a self-inflicted loop of finding knocked up characters that had to give birth, escorting them to medical, and filling them back up only to have another 3 waiting in the same situation. The timer for those kept going regardless of in-game time.
2) pills have a tendency to disappear into the ether while trying to offer them to subs. It looks like anything to do with the milking machine will override the conclusion to the drug offering prompt, so the pill will disappear from inventory without being applied, or a notification that they made you drop it. Might be game mechanic issue, or just an issue receiving the notification.
3) belly growth looks kind of weird when you get to larger sizes, and starts looking like a weird long bean instead of a pregnant belly, but that is with the "belly scales with number of children" option enabled. Relevant to the next point
4) less of an issue than a suggestion, maybe once reaching pregnancies above a certain size (i.e. 20 kids) the character ends up immobilized for the latter part of pregnancy, similar to the stocks? Could have multiple thresholds, 20 kids ends up immobilized for third trimester, 40 by second, 60 is immobilized as soon as they start showing. Would need a sort of timelapse mechanic like resting in the stocks to avoid locking the gameplay.
5) skills are easily powerleveled by just continuously fucking the same character over and over again, particularly exhibition, sex slave, cum lover, and breeder. This ties in to the frozen clock issue I mentioned before, where you can continue going without having to worry about the time because the "night-time" indicator doesn't change until you go to sleep.
6) relevant to point 5, there aren't very many perks available with some of the ridiculous levels that skills get to. I've reached a point where I have over 50 skill points available in cum lover and breeder, and about 25 in exhibitionism and sex slave, but all perks have already been chosen. If not a number of additional skills, since I assume it's pretty difficult to come up with unique skills, then maybe attaining a certain high level could unlock new capabilities; experience stretching out and growing certain parts of the body allowing you to try vore (if that is in any way an interest of yours, of course). Say, breeders have honed their balls to hold so much cum they can now hold an entire person, with additional perks like increasing the held character's virility or knocking them up with the constant bath, or experience with fertility and birth now leaves you open enough to carry another in your womb, with the potential perks of increasing their fertility and lactation.
7) any time a character has contraband pills, there really should be a way to convince them to hand it over that isn't beating them up; it's rather demoralizing to see a character you've built up a good relationship with express disappointment that you're attacking them. Maybe if they have an affection level above 50% you can just ask them to hand it over?
8) characters' likes and interest don't seem to have much consistency; a character that loves big dicks will turn around and hate nudity, or a character that loves lactation will turn around and hate breasts of any shape that isn't flat. Or they'll love seeing any used hole, but hate nudity, or love seeing a stuffed butt, but not exposed anus.
9) fertility leveling makes no sense; sometimes a single birth grants more xp than twins, but less than triplets? I just got my character to give birth to 293 kids with the superfetation perk, but didn't gain a single level from it. Some sort of consistency and sense there would be great.
I'm still fiddling around with it, but those are a few things I've noticed so far, sorry to be the paragraph guy.