See this lies what I perceive as a flaw. They are
slaves, you are not supposed to corrupt them, just to break their will. They can obey or revolt, but this is where all stops. It's not a dating simulator, ffs. Walks on the beach? Look at the stars? Go to a dinner with them? Seriously? I repeat, they are not escorts or girlfriends. They are sex-slaves.
Everything is made backwards. In game you are supposed to befriend them then sink them in depravity, when in fact they should see the depravity / prostitution / weird kinks / etc as an escape from sub-human slave condition and embrace it with all their strength. That girl from slave market - the one that costs 8k - have the nerve to put conditions "treat me with respect". The other one that advances the story - you are supposed to break her - goes "i will play my part and act like your servant". I own your ass, bitch, I could (read should) skin you alive and hung you by that tongue. But player is not given this option. Best he can do is "punish" them with a double dildo.
DownTheDrain is right. Slavery part was the least entertaining in all the game. You don't feel like a slave master, more like a husband with many wives. I ended up spending my days fighting bandits in town, doing arena and recycling loot. Had no desire spending time with the girls. And I dare say, for a sex-game that's pretty bad.