What I mean is, before player can spend slave's AP for MUP, they have to get the minimum obedience first. Without it, it's just too easy to get MUP. Like in my first game, I have a bunch of MUP without having to sell a single well-trained slave.
Viewing post in [Suggestion] About Attr Points
Imo your suggestion makes sense. I think it would be still too easy, though: once you buy the alchemy room and unlock the right spells, you can make a slave obedient the same day you have captured her (or the day after, if you just rape her).
I would add an additional constraint: she must have lived with you a whole week at least (metrics.ownership >= 7 . Or metrics.ownership - metrics.jail >= 7 if you do not count the days spent in prison).