Well, you can upgrade your dungeons and brothels to make them nicer, and raise girls' spirit. Maybe include an upgrade for cameras in the girls' rooms at the brothels, to hasten guards' response, to make them feel safer. Or decorate the place with flowers. You can have "High Class" accommodations, but I've always thought where they live and where they work should be separate. That too can be a gold dump, since you'd have to buy their homes, as well as the brothel.
It would open up several possibilities, at the least.
You'd have an apartment for the girls to live in, and you can send a certain number of them to the brothels. That number will actually work there. You can buy different apartments to allow different accommodations. Before you can get "Adequate", you need to buy it.
Make the costs go up as the levels of accommodations become more varied, and lower the cost of actually setting them there.
It would make a bit more sense than being able to set a girl to high class, then the very next day, to adequate. How would you do something like that? Send in your gang to hammer the place to the ground?
An alternate way of doing this is... to make it, like brothels, that you can buy apartments in better and better parts of Crossgate. But the apartments are basically all the same. The only difference is that you can upgrade the ones in the better part of Crossgate further and cheaper than the ones in the worse parts. In the worst one, you can't even hire a maid for a realistic price, because they fear they'll be enslaved there. In the best ones, you can hire a whole team to take care of the place. The worst ones are much more likely to be attacked, and girls kidnapped, if you don't protect it with your gang. As it goes on, you can include a security system for a very high price on the worse ones. Basically, you'd be paying the builders much more to upgrade it because of fear.
Sorta goes on like that. I sort of went on a tangent there. I get ideas all the time...
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But keeping with the idea of "good" dungeon upgrades... it would play out essentially the same way. You can include candles, a secured hot springs for them to bathe in, floral patterns... you can even include a job for girls to talk to them instead of torturing them, which will lower their fear and hate of you, and increase their happiness. For each girl you put on that job, they'd do 10 conversations with the first girls in the list that haven't been talked to that day.
Understand, or do you need more?