@Aika,
Thanks for the defense, but I wasn't all that bothered by the original response. To be honest, I did feel that my post was lacking something, some of the ideas in my head were a little...disconnected.
@Xela,
To be clear, I was trying to ponder the motivations that would be behind the actions of a 'Free Girl' and a Slave. I was thinking back to early American History, and for the most part, Class Mobility is a driving goal for many Freemen. In the world of Crossgate (WM) that may not be a realizable goal, as you pointed out. Even still, there should be motivations and what those are and what effects they will cause could be useful to know.
If you are a Slave(in WM), what motivates you each day? How hard do you work, and why? Ask the same questions if you are a Free individual. What are your motivations? The differences in the answers to both types of persons(Slave & 'Free Girl') may provide insight in how to balance them in-game. These kinds of advantages/disadvantages could be added to the game.
Switching topics, when I was contemplating accommodations (upkeep), I imagined that each brothel had a set of rooms(upstairs?) that could be used for lodging. But while a Brothel may employ up to 20 girls, maybe only 10 rooms were available. As the PC, you could provide for 10 girls at a time, and the other 10 would have to lodge elsewhere. This means at a minimum, 10 would have to be 'Free Girls'. You could as well have only 5 Slaves, and 'Rent' out the remaining 5 rooms to 'Free Girls' you are employing. In this case, I am just picking random numbers, no thought as to balancing yet, but this mechanic--while maybe difficult to code--also limits Player choices. Something that may not be desirable.
Switching to "Slaves as Security", my initial reaction is, who cares if a Player wants to arm a Slave? If the PC wants to risk arming a Slave who will later rebel and escape with a few other slaves, so be it. Just because it isn't a wise decision, doesn't mean it should be coded as impossible to make. I could imagine a rare situation where a slave becomes so infatuated with the PC where she would willing serve his every command, and she could be trusted with weapons. I am thinking of a Shampoo(Ranma 1/2) personality type, who would literally do anything if she thought it would please her master. Would it be completely unreasonable to trust her with weapons and the task of protecting your Brothel?
However, if it is easily possible to train Slaves to have that undying-devotion to their Master, how would that affect their balances with 'Free Girls'. A Slave motivated by pure love to that degree, would be nearly as effective at performing jobs as a 'Free Girl'. Even better at some as she wouldn't refuse her Master's commands. Though I supsect that even a 'Free Girl' could be trained to the same degree and she might be willing to take a steep pay-cut, if she thought it would benefit her Love. I suppose the conclusion that could be made from this, is that their needs to be a balance to the PCLove stat that girls will have. There would need to be downward pressures on the stat to prevent a Player from easily making all girls in his employ madly in love with him that they would heed his every beckon and demand nothing in return.
Just some further thoughts. As Aika said, I am only throwing this out as brainstorming ideas.