It's a dungeon crawl, so yeah, I'd say that searching is in-genre. But the problem is that there seem to be two standard ways of handling it, and neither one is satisfying:
- Option 1: "We check the east wall. Any secret doors?" (Optional: "Roll Perception." "12.") "No, you don't find any." "We check the west wall." "No doors." "Okay, we move 10 feet south. Any doors on the east wall?" This is excruciatingly tedious, and you can sense that everybody at the table is bored, but they don't want to miss a door.
- Option 2: "You see a 30-foot hallway leading south. Player A with the high passive perception score, you notice a secret door in the east wall." This completely negates the point of having a secret door in the first place, because it's not actually secret.
Making it so that some of the doors are findable with passive perception and some are not just seems likely to lead back to Option 1, except with even fewer successes to break the monotony.
It seems like there's got to be a sweet spot somewhere, where the players can drive the search and finding the doors is still a product of their own initiative, but where they don't get bored spending a large proportion of the time on unsuccessful searches.
Maybe dividing up the dungeon into segments larger than one room (or length of corridor) at a time might work? Have them explore a portion of the dungeon first and then either make a roll at the end to see if anyone noticed anything along the way or tell the character with the highest passive perception, "You remember noticing a crack in the wall three rooms back."
There's also the
wand of secrets, but it only has a range of 30 feet and it has a limited number of charges.