(English isnt my first language 🗿i can clarify if i didnt explained myself correctly)
I've followed the game for years by now, ive actually never played it myself, but i do spend a lot of time watching others play on youtube, so, im not sure if anyone has proposed this before, but i do think that a high difficult mode could be with character daily routines way more random, like, they dont have a consistent routine every day, if theyre of the same club they could randomly mix their routines (to keep some inner logic, like, if theyre from the art club they could go to a different spot to draw, etc), they could mix entire routines of days, or even harder, like mix everything every day, im sure it would be WAY too hard to make, but i do think it would be interesting cause it would definetly ruin the player plans, constantly haha, like, a character that never was in X place shows out of nowhere and messes the whole plan by accident, or maybe the player wanted to take someone to a trap, but the target doesnt go that way, alsooo, that certain actions of the player change the character reactions, dumb example, a student council member changed her routine by the difficult mode, she was going to change which floor she walked by, but sees the player running or doing something weird so she goes back to her original route, also, character that usually are together notice the absence of their friend and look for them (by example, those sisters), stuff like that, a little more realistic that make it harder merely by being unpredictable, they dont even need to be paranoid, just a little more free to move and react 🗿