The most important thing about a stealth game is that it needs to be fun and interesting to get from "Point A" to "Point B". The player must be given multiple paths to their destination, and must be given multiple options to bypass the obstacles in their way.
In terms of level design, my priorities are:
1) Fun and interesting options for reaching destination, and challenging obstacles to avoid.
2) Making a Japanese high school that feels authentic.
When you look at Yandere Simulator, you might see
this, but I see
this.
Let's create a hypothetical scenario:
https://imgur.com/4Yp4mbu.png
You need to get from one end of a hallway to the other end without getting spotted. Maybe you're carrying a corpse and need to get it to the incinerator to dispose of it, or maybe you're covered in blood and you're trying to get to the locker room. Either way, you need to get down this hall. (Other halls are available, but they all have similar obstacles to the ones I'm about to describe.)
There are a bunch of students in the hall, basically forming a "wall" that makes it impossible to just walk straight down the hallway without instantly getting spotted by everyone. To make matters worse, let's imagine it's the Student Council.
To get down this hall, you're going to have to pass through the faculty room. Inside, the gym teacher is patrolling, walking in a circle around the room. You'll have to open the door to the faculty room, take note of her patrol path, then slip into the room when she's facing away from you.
Then you'll have the task of figuring out how to exit the room without the student council spotting you as you exit. Probably the most straightforward solution is to activate something that makes noise at the top corner of the room; for example, bringing a radio into the room and activating it at the top-right corner of the room (with the door closed) to make the whole student council turn and face it (but only when the gym teacher is far enough away from the radio to not hear it and instantly turn around and face you).
In short, I imagine each room of the school like a miniature "VR stealth mission" from Metal Gear Solid. How does the player navigate through it? How does the layout offer hiding spots? Take a look at the student council room:
https://imgur.com/HcGAN1B.png Do you know why I put those L-shaped bookcases there? Those are hiding spots for the player to hide in while sneaking through the room. Every room has been designed with this sort of thing in mind.
...or, at least, that's the way it's supposed to be. I'm currently very dissatisfied with the layout of the school, because I don't believe that it provides enough "stealth opportunities". I've stated many times that Yandere Simulator is actually a "social stealth" game, and that the "stealth" here is keeping your true nature a secret and being a social chameleon, rather than actually physically hiding...but I do want the layout of every room in the school to facilitate stealth gameplay, nonetheless.
So, my question is: how would faculty toilets and a faculty kitchen facilitate stealth gameplay? If the answer is "It has nothing to do with stealth or creating opportunities for the player, it's just to make an authentic high school" then it's going to be very low on my priority list.
*
(this is what the person originally asked about, he didn’t just suddenly burst into teacher-toilet talk)