I'm sure someone in the past has suggested this \ it crossed your mind, but using LLM technology (with some RAG probably) could enable players to freely interact with their slaves to train them in a unique way. After a long time of playing you just skip the familiar texts, and something like this could breath life into the game.
The problem with it is that not all players could run this fast, making this an optional feature for some. If you want a much cheaper and accessible-to-all solution, imagine what if every girl had her own shit ton of unique text that has references to small stuff in her personality and history. The various slaves would feel different not only in images and art. One way to utilize LLMs to do that, for example: generate 20 unique texts for each situation (e.g., morning bj), then use another LLM ("LLM-as-a-judge") to automatically rank and filter the top 5 best unique texts to remain for that character. you could add a layer of manual checking to this to verify it's good. Just imagine that when pressing a button to humiliate Aisha the MC would reference her insolence during their first meeting, or mentioning her father running away. This would make players read the dialogue and add a ton of depth without forcing you to hire a full time writer for that.