Already posted on this a while back, but I've got nothing better to do while waiting for the P-Cup DLC:
ART:
Futanari: Both Karryn and inmates (but preferably inmates). Either add futanaris to the enemy roster, or turn all enemies into futanari versions. Requires new SFX as well.
Bimbo: The option to turn Karryn into a slutty bimbo.
Ahegao: An even more depraved face for Karryn.
BDSM Outfit: A full BDSM slave outfit for Karryn.
MECHANICS
Pregnancy: Already got mods for this, but I'd make it official as a developer. Also, an in-game tally would be nice.
Incest: To go with pregnancy.
Lactation: To go with pregnancy, where Karryn has to milk her breasts regularly, either in or out of combat.
Public Pillory: A pillory for Karryn to be used by the general public, without the emperor's knowledge, of course.
Nurse: I mean, the door to the infirmary is right there!
Rancher: A part-time job in the ranch on level 4. Could introduce bestiality here, and even put a lactation-device here.
ENEMIES:
Bestiality: We've got werewolves, yetis and slimes, but they all feel humanoid-sentient. I'd love to have Karryn degraded by animals like horses, bulls, pigs, dogs, etc.
Nuns: Perhaps some sort of sadistic support enemy variant of the nerd, but they work for the guards instead. Either have them wear strap-ons or become futanaris.
Tentacle Monster: Could come in many variants. Plants, octopuses, eldritch, etc.
Hypnotist: An enemy that hypnotises Karryn into submission.
STORY:
Cuck Emperor: Let the emperor know what Karryn's really doing, but he loves it deep down. Karryn still has no idea he knows. Perhaps also introduce some NPC's that knows the emperor personally (nobility, state officials, high ranking officers, etc.), that fucks Karryn "behind the emperor's back".
If I had to pick only three of these, I'd pick futanari, pregnancy and incest.