That does make it less deterministic when building the environment, which is nice. However, the PC with the greatest passive perception check is still the source of all perception for the party in most circumstances. That is, anything a given PC can find the PC with greatest passive perception can also find, and anything the PC with greatest passive perception can't find can't be found by any PC with a lower passive perception.
Exactly. Rolling a trap / environment check vs. Passive Perception was the first and most obvious solution that came to my head too. Then I realized about a minute later that it made only the highest passive perception in the party matter, and then I concluded that such a thing was incredibly lame and took away one of the most simple and fun parts of helping to explore when you're not the designated trap-monkey of the party.
I was taken with the idea of a static vs. static comparison (the trap / hazard / secret has a Passive Stealth score) and then rolling a single check against a random member of the party to add the variance back in while giving everyone a chance to be useful (or a liability).
This is what I'd prefer:
At Feature Generation: Each hazard / trap / secret has a Stealth Modifier equal to a die roll range. A poor quality or obvious hazard might range from a penalty to a small bonus like -2 to 3 (1d6-3) while a devilish trap might run from 4-9 (1d6+3).
At Encounter Time: First, make a Stealth Check for the feature (d20 roll + modifier) against the Passive Perception of a random party member. On a failed check that character spots the hidden feature. On a successful check, add the feature's Stealth Modifier to 10 to to get its Static Stealth value. It is noticed by any other character with an equal or higher Passive Wisdom (Perception) check.
This method scales from solos to large groups without increasing overhead. It also makes having a point-man an asset without making the perception skills of all the other party members a moot point. It also adds some old-school randomized volatility for a dungeon crawl to keep the exploration pillar lively.
- Marty Lund