graffiti could occasionally be specific to your run

Once youre familiar with all the stock graffiti, there's few reasons to read them anymore Maybe once in a while they could reveal something specific to your dungeon. Perhaps a note from an old adventurer, saying they left their +4 chainmail on level 1200. Or reveal the existence of an armorer on level 800 etc. Or maybe simpler, just a graffiti warning you not to drink a certain potion (without identifying it exactly)