I guess you didn't code this part yet.
Which part?
0. Before I forget again, signboard! You know, if you don't have whores in the current brothel then you don't need horny customers, etc. I have already mentioned it somewhere.
Ok, so no signboard, no costumers basically... makes sense. All advertising and updates came from the original concept of making a copy of the Original Simbrothel first, before moving to WMlike version. Still I had to agree with everyone who said game would be to shallow without proper items system and degree of events and interaction I planned for SimBro version...
1. Even if we don't have areas yet, we still could use 'em. We don't even need names using some variable like "arealevel" from 0 to 5. The better the area, the richer and more demanding customers.
We can leave placeholders for areas codewise, I meant positioning on the map is close to impossible at the moment, I do have some thoughts on how to do it now but it is premature.
3. Security level. It is one of the main game's stats in wm and wm ex, after all.
Like a deterrent... better security = less negative events... we can do that.
4. Time period between building upgrades or new rooms? And maybe no more instant building too?
Blah

I cannot see any added value to the game in it.
5. Maybe also some variable for general condition of the building (maybe even instead of taxes), so you have to repair it sometimes, especially after group fights with customers or competitors inside the building with using large-scale magic
Maybe... but not like in SimBro 1x. Castles there are loosing structural integrity every 10 or so days

We could add repair costs of some kind, it's really simple code vs decent added value to the game.
I need to think more about the Next Day part, but it's already obvious that the current next day interface is very undesirable even for testing. We need at least wm-like one.
I hate WM like one, preferring the one with listing. But I will obviously improve Next Day interface and add filters.