I've been thinking about this for awhile, and I would like to see the ability to 'design' rooms. either buy being able to buy items and put them into a brothel inventory, or a new spot in the girls inventory 'room items'.
these would/could effect the accommodation levels, the pleasure received by both the girl and customers, and cost the girls could demand/receive, and even attract customers.
some types of items would be pictures, furniture, tvs (which could increase movie sales), permanent flower arrangements (which would increase/create a building upkeep), gardens (for fetishes taking place outside, or for girls to relax in), rugs, and bathroom facilities.
if the brothel inventory is used maybe we could have a different shop for these items, so they could be categorized like the girls inventories are, and limits placed so that you don't have 20 couches and 20 beds.