Throwing out a question to experienced DMs out there regarding passive perception, and to a directly related second part, hidden hazards.
I find the language used around passive skills to be a little unclear in the wording, and I'd like a little clarity on what other peoples interpretations are. One of the characters in my campaign has a particularly high passive perception, and following the rules as I understand them, I need to point out anything to that player that they can see which they would have made with an active check. This has basically made hidden objects and traps a completely trivial mechanic during dungeon crawling.
To explain with an example, last session I had the party exploring an abandoned mine shaft, but having the Gloom Stalker ranger (with a passive perception of 18) up front they powered though the scenario I'd made without any fear as I pointed out every hazard to them well before they got near it (Umbral sight seems to be completely ridiculous too, but I gotta pick my battles). Sure, I could have just upped the DC on finding them to 19, but that feels like punishing all the other players (who don't have a very high perception skill) with an unreasonably difficult check.
Semi-related, but I also find it very difficult 'springing' traps on my players when that does come up. It's a bit awkward with the fussing about stopping the part in its tracks and asking everyone "uh okey hold on, show me -exactly- where you're standing." This is much more a problem for a '5x5 foot trap in a 20x20 sized room' (rather than something that takes up the width of a corridor), so I guess this is more contextual to the type of trap and I should just stop using those..
Obviously I don't want to sadistically inflict traps on my players, but if it's my job to provide the drama to the game I've found it difficult to do with what is kind of a staple to the dungeon crawl.
In my campaign, I tell mt players that I do not use passive perception (or flanking or AoO) since it can really undue the mysteries of entering a dark and gloomy dungeon or an oppressive as well as horrific forest. It basically spoils the whole mood of the game. So what I do have the players do when traversing such things as a dungeon or what ever else is out there is to make perception DC checks, perhaps at DC levels 12 or 14 depending on the characters level. So for example the players are traversing a dungeon corridor and something is hiding in the shadows to jump out at them, then it is the players perception vs the sneaky dudes stealth to see who has the surprise on whom.
Just wait until the rogues in your party become 9th or 10th level, then it will become real good times for the dungeon master as they use their bonus actions to disappear in thin air (just like World of Warcraft) and perception becomes even more vital. Anyway hopefully that helped ya.
Simply put, too high of a Passive Perception is a Surprise buzzkill most of the time. The only way as you noted to provide DCs of any challenge to the PC, is to up them. One way to do that is through Contests or use an active skill check by an NPC that has to be countered with a passive or active PC check.
Contests
Sometimes one character's or monster's efforts are directly opposed to another's. This can occur when both of them are trying to do the same thing and only one can succeed, such as attempting to snatch up a magic ring that has fallen on the floor. This situation also applies when one of them is trying to prevent the other one from accomplishing a goal — for example, when a monster tries to force open a door that an adventurer is holding closed. In situations like these, the outcome is determined by a special form of ability check, called a contest.
Both participants in a contest make ability checks appropriate to their efforts. They apply all appropriate bonuses and penalties, but instead of comparing the total to a DC, they compare the totals of their two checks. The participant with the higher check total wins the contest. That character or monster either succeeds at the action or prevents the other one from succeeding.
If the contest results in a tie, the situation remains the same as it was before the contest. Thus, one contestant might win the contest by default. If two characters tie in a contest to snatch a ring off the floor, neither character grabs it. In a contest between a monster trying to open a door and an adventurer trying to keep the door closed, a tie means that the door remains shut.
Traps and hazards have DCs generally set by static difficulty tiers(as shown below) but, nothing says an NPC can't set the DC for traps with a skill they possess. Also, it is not unreasonable to set more difficult traps and hazards for the PCs in some cases.
There are plenty types of traps. In my opinion it is ok for someone with high passive perception to notice them. It is a whole different matter to solve the type of trap for safe passage. When players invest in something very specific it often comes with a trade off in another area. Just accept it being there instead of punishing the player with meta bullshit.
Step 1: Who placed the trap? How much time to hide the trap did that creature have? What would be a sensible Hide check for them to cover the trap in question in that scenario. Step 2: what kind of trap did they make? how elaborate is it? Because after spotting a trap the party needs to investigate it to see how it functions and try to disarm it. You can turn this element in a small puzzle or small mystery investigation style as well if that is something your players enjoy. It also promotes team play since you had the Gloomstalker spot the trap. However he needs others to help in taking it apart for safe traversal
As for the comment regarding a claustrophobic and horrific atmosphere can be achieved in many ways. There is narration using pictures and other tools to show at the table to set the tone. Play with the Vision of the players with enemies that can hide just out of their range of sight. Occasionally dropping on them from all angles followed by a passage with just water drops and spiderwebs hitting them in the face while being described more vaguely. Describe smells, how shadows move at the edge of their view even if its just a stalagtite etc. Use music in the background to set the vibe as well for what you seek. I find the sound track of Axiom Verge really freaky for example and used it during a sci-fantasy horror one-shot. If such atmosphere depends heavily on the usage of traps there is something wrong.
Not using passives and having players make constant checks every 5seconds just adds to the tediousness. making things more frustrating then they should be. and takes away part of character development/specialization. Then again when going through a dungeon...Within a room or two you can assume that characters switch to active perception and looking out for things. As DM you can then rule to make Spot checks even though they're lower then a passive score. Because passives just do a general look around an area. They might catch a breeze coming from a certain direction as a hint. Which gives the player the chance to decide to describe what they do and on which wall in roleplay fashion. To which the DM then asks for an active spot check to notice the details of where the trap truly is.
When going through a corridor. the bottom half of the walls are covered in detailed braille depictions of a certain scene/culture. There are fire braziers every few steps alternating the side of the wall they're on. Nothing looks out of the ordinary. Cept for the gloomstalker that faintly notices some black liquid on the wall behind one of those flaming braziers. <--- he doesn't know it is truly a trap, he doesnt' know where exactly the trap is nor how it functions. So when another PC runs their hands over the braille art without checking for a trap they accidentally press a small button. Behind the braziers slits open up and gouts of black oil spew out of creating a flame thrower effect. Trap is sprung. Players have to evade the flames and get the hell out of the corridor as the floor is starting to fill with some sort of flammable tar. Describing every few seconds how it rises up and starts to create difficult terrain and slowing the movement speed. Hope this is a clear enough example I've used recently.
Ps. it would've been funnier if the gloomstalker in said example would roleplay how he'd follow the trail and do a spot check. to find that some tiles have different colorastion. The other PC presses the button by accident at that same time causing the slits to open and oil to be blasted in the Gloomstalker's face. Making sure his vision will be obscured for quite some time. And should he also be unlucky to get hit by the flame in the face... well that's leaving a nasty burn scar. Adding flavor to the character.
Id be careful with upping DC or ignoring pass perception without talking to the player about it because their build could have been intentionally geared on the RAW and to find out they are now pretty useless could be annoying.
Rollback Post to RevisionRollBack
All posts come with the caveat that I don't know what I'm talking about.
I love passive uses of skills as they speed the game up no end - that said in one game that I am running there are 8 players. Passive skill allows me to tell them what they notice, but they have to still be looking. So if they are randomly walking down the path reading the merchant's price list then they aren't looking around them for danger. They might still hear a wild animal approach but anything that is purely visual they might miss and so roll for it.
Increasing the DC is a bit of a ****** move I think because to get a perception that high at low level would require heavily investing in wisdom, getting expertise and or the feat that adds +5 to passive perception. That player has actively focused on becoming good at that ability to the exclusion of other abilities. Punishing them for that is a little unfair. Someone else also mentioned that yes while they might see the trap, they still have to get around it somehow. Traps and locks may be their thing though, that may be what they love doing. I have a player who is really orientated on that and so I add extra and provide more intricate and detailed ones because that's his area to shine during a session..
There's some dispute both about how passive traits are intended to work, and about how they should work. In general someone taking Expertise (Perception) is saying "Hey, I don't want to ever be surprised by stuff".
My general rule for passive scores is that they're targets -- I will make a check for the trap against a DC of the passive perception of the leader -- but that's not RAW.
Id be careful with upping DC or ignoring pass perception without talking to the player about it because their build could have been intentionally geared on the RAW and to find out they are now pretty useless could be annoying.
I definitely feel that this comment and "meta gaming bullshit" and "***dick?*** move" is directed at me, LOL! That's fine, I only posted RAW examples on how to increase difficulties if you feel it's warranted, it's right there in the rules so, obviously it occurred to the designers.
I can tell you from experience, playing with another PC who has Observant feat making his Passive Perception 22, is Hella Boring. The guy has to be actively doing something else or asleep to not notice anything less than Hard on the DC table.
Other Activities
Characters who turn their attention to other tasks as the group travels are not focused on watching for danger. These characters don’t contribute their passive Wisdom (Perception) scores to the group’s chance of noticing hidden threats. partial quote.
Not really aimed at anyone. I'm also not disagreeing with it being a solution. I'm just saying that it should be laid out to the player and probably with the option for them to change their character.
If they have been spending "resources" [point buy, asi, feats] to get a really good passive perception at the cost of not being good at other things and then you change it unilaterally their charcter looses all power and is now likely to be weaker at the things that you have left untouched.
Id say the same would be true regardless of what it is you change half way through.
Rollback Post to RevisionRollBack
All posts come with the caveat that I don't know what I'm talking about.
While I know what you are saying, let me put it to you another way.
If a character was built by a players who's main goal was to have the highest AC possible(this is a common goal), would you just allow him to be virtually untouched by physical combat? Most DM's wouldn't. They would either create something that had a chance to hit the PC or go with an even more dastardly plan, like undermine their whole impenetrable defense concept by spell checking their weak stats.
Now before you say this is also unfair, I use this example because it relates to my own Fighter character. I have Plate, Dual Wield, Crit Immunity, Freedom of Movement, Heavy Armor Master, very good Str, decent Dex and Con. I'm sure you get the picture. To challenge me physically, you need to throw in Giants and other big scary monsters my way. To challenge my average stats of Int, Cha or Wis...it doesn't take much. I am perfectly fine with being spelled up because I trust both my DM and the other players to throw me a lifeline and keep me in the game and relevant.
So, should I have "the talk" to change my character because, as you put it, "If they have been spending "resources" [point buy, asi, feats] to get a really good passive(defenses in my case) perception at the cost of not being good at other things and then you change it unilaterally their charcter looses all power and is now likely to be weaker at the things that you have left untouched"?
I think that's pretty unnecessary. I shouldn't be an untouchable juggernaut all the time but, sometimes I am! That's moderation. In my first response, I said: "Also, it is not unreasonable to set more difficult traps and hazards for the PCs in some cases", that's not changing things unilaterally. That's changing things with moderation and forethought.
I can't take credit for this idea, but I have run with it since I read it. For me, passive skills are only used to oppose active rolls because someone should always be rolling.
Even if a character has high AC. It doesn't make them virtually untouchable. Flanking and/or Aid/Help rules will grant advantage for enemies to attack. "sacrifice" a creature to knock the PC prone. Allowing others to get close and gain advantage. Combined with other tactics and the multi-attacks that PC will still take plenty of hits. Having such a high AC isn't a big issue since that character will have crappy Int, Wis and/or Charisma. You can easily wound and deal with them if using the tools the game presents. It is not dastardly at all as long as the enemy you put in front of them makes sense to be there. And of course not use them every time.
Cleric at my table. I've let him gain proficiency in heavy armor. because i'm nice like that. With spells and such he can go from 21AC to 23-24. 2 Hobgoblin Iron Fists can deal with him in physical attacks just fine. Just use proper tactics and plenty of their multi-attacks will land. taking him down gradually without him being able to even land a hit in between due to Shadow Jaunt. He got cocky for being "unkillable" for a while. Use that overconfidence against them. Especially since the past they had a fight with an AoE charm effect as lair action. That wiped out almost the entire party. So its isn't as if the player is unaware of the trade off and risks. The decision of how to build and invest in their character is theirs in the end. Let them enjoy that investment in both the pro's and cons.
@texas
I suppose that would depend on the situation. If someone tries to scry and does an active role. Then using the passive perception of the PC to notice it makes sense. especially if you're written it down and don't have to ask the player for the number. Otherwise you'd be giving it away regardless. seeing how most people meta-game whether they try to or not. It makes sense to do it this way.
I have a character who recently picked the Observant feat and I'm still struggling with how to play it without giving every secret every time, but without making the player feel like they wasted a feat.
I dont think that particularly changes my initial statement of being careful about changing it [and any mechanic] part way through a game.
The AC one both fit in the same type of encouter. Even targeting your weaker stats with spells wouldnt detracted from you still being pretty much untouchable for physical damage. Where as removing/altering perception could take out someone's whole vision of being a scout at the expense of being less effective in combat.
However both seem to agree that depends on the table...
Rollback Post to RevisionRollBack
All posts come with the caveat that I don't know what I'm talking about.
I have a character who recently picked the Observant feat and I'm still struggling with how to play it without giving every secret every time, but without making the player feel like they wasted a feat.
You don't. I recommend asking them to take a different feat.
I have a character who recently picked the Observant feat and I'm still struggling with how to play it without giving every secret every time, but without making the player feel like they wasted a feat.
You don't. I recommend asking them to take a different feat.
I think I will do this. I really don't want them to waste a feat on something I'm not into from a narrative standpoint.
Just let them have the feat. If I understand it just lets you lip read. and a +5 to passive perception and passive investigation. Lip reading can be dealt with easy enough with obvious ways. Telling a player not to take something for these kinds of reasons is such a cheap cop-out.
Having a 20 perception/investigation doesn't meant they see and solve everything. Passive means a very global general view of what is going on. That player will more easily notice that something is going on and find 1 or 2 obvious leads and that is it. When designing an investigation you usually create multiple scenes/environments. With 3-4 clues per location. Ranging from the very obvious that you see upon entering the area. Some moderate clues. And clues that are more obscure and require a closer detailed look. The player with the higher passive will just notice the obvious clue and something that'll draws their eye to the moderate clue. That is all. The rest is still up to roleplaying, further and actual active investigation and putting the pieces together. And in a previous example I already showed that a high passive perception will NOT automatically find the trap and know how to disarm it. They're just aware something is up and find the first clue to finding the trap.
By unnecessarily banning such a feat means you take away the chance for players who want to play Sherlock Holmes type of characters.
Throwing out a question to experienced DMs out there regarding passive perception, and to a directly related second part, hidden hazards.
I find the language used around passive skills to be a little unclear in the wording, and I'd like a little clarity on what other peoples interpretations are. One of the characters in my campaign has a particularly high passive perception, and following the rules as I understand them, I need to point out anything to that player that they can see which they would have made with an active check. This has basically made hidden objects and traps a completely trivial mechanic during dungeon crawling.
To explain with an example, last session I had the party exploring an abandoned mine shaft, but having the Gloom Stalker ranger (with a passive perception of 18) up front they powered though the scenario I'd made without any fear as I pointed out every hazard to them well before they got near it (Umbral sight seems to be completely ridiculous too, but I gotta pick my battles). Sure, I could have just upped the DC on finding them to 19, but that feels like punishing all the other players (who don't have a very high perception skill) with an unreasonably difficult check.
Semi-related, but I also find it very difficult 'springing' traps on my players when that does come up. It's a bit awkward with the fussing about stopping the part in its tracks and asking everyone "uh okey hold on, show me -exactly- where you're standing." This is much more a problem for a '5x5 foot trap in a 20x20 sized room' (rather than something that takes up the width of a corridor), so I guess this is more contextual to the type of trap and I should just stop using those..
Obviously I don't want to sadistically inflict traps on my players, but if it's my job to provide the drama to the game I've found it difficult to do with what is kind of a staple to the dungeon crawl.
In my campaign, I tell mt players that I do not use passive perception (or flanking or AoO) since it can really undue the mysteries of entering a dark and gloomy dungeon or an oppressive as well as horrific forest. It basically spoils the whole mood of the game. So what I do have the players do when traversing such things as a dungeon or what ever else is out there is to make perception DC checks, perhaps at DC levels 12 or 14 depending on the characters level. So for example the players are traversing a dungeon corridor and something is hiding in the shadows to jump out at them, then it is the players perception vs the sneaky dudes stealth to see who has the surprise on whom.
Just wait until the rogues in your party become 9th or 10th level, then it will become real good times for the dungeon master as they use their bonus actions to disappear in thin air (just like World of Warcraft) and perception becomes even more vital. Anyway hopefully that helped ya.
Simply put, too high of a Passive Perception is a Surprise buzzkill most of the time. The only way as you noted to provide DCs of any challenge to the PC, is to up them. One way to do that is through Contests or use an active skill check by an NPC that has to be countered with a passive or active PC check.
Contests
Sometimes one character's or monster's efforts are directly opposed to another's. This can occur when both of them are trying to do the same thing and only one can succeed, such as attempting to snatch up a magic ring that has fallen on the floor. This situation also applies when one of them is trying to prevent the other one from accomplishing a goal — for example, when a monster tries to force open a door that an adventurer is holding closed. In situations like these, the outcome is determined by a special form of ability check, called a contest.
Both participants in a contest make ability checks appropriate to their efforts. They apply all appropriate bonuses and penalties, but instead of comparing the total to a DC, they compare the totals of their two checks. The participant with the higher check total wins the contest. That character or monster either succeeds at the action or prevents the other one from succeeding.
If the contest results in a tie, the situation remains the same as it was before the contest. Thus, one contestant might win the contest by default. If two characters tie in a contest to snatch a ring off the floor, neither character grabs it. In a contest between a monster trying to open a door and an adventurer trying to keep the door closed, a tie means that the door remains shut.
Traps and hazards have DCs generally set by static difficulty tiers(as shown below) but, nothing says an NPC can't set the DC for traps with a skill they possess. Also, it is not unreasonable to set more difficult traps and hazards for the PCs in some cases.
Typical Difficulty Classes
There are plenty types of traps. In my opinion it is ok for someone with high passive perception to notice them. It is a whole different matter to solve the type of trap for safe passage. When players invest in something very specific it often comes with a trade off in another area. Just accept it being there instead of punishing the player with meta bullshit.
Step 1: Who placed the trap? How much time to hide the trap did that creature have? What would be a sensible Hide check for them to cover the trap in question in that scenario.
Step 2: what kind of trap did they make? how elaborate is it? Because after spotting a trap the party needs to investigate it to see how it functions and try to disarm it. You can turn this element in a small puzzle or small mystery investigation style as well if that is something your players enjoy. It also promotes team play since you had the Gloomstalker spot the trap. However he needs others to help in taking it apart for safe traversal
As for the comment regarding a claustrophobic and horrific atmosphere can be achieved in many ways. There is narration using pictures and other tools to show at the table to set the tone. Play with the Vision of the players with enemies that can hide just out of their range of sight. Occasionally dropping on them from all angles followed by a passage with just water drops and spiderwebs hitting them in the face while being described more vaguely. Describe smells, how shadows move at the edge of their view even if its just a stalagtite etc. Use music in the background to set the vibe as well for what you seek. I find the sound track of Axiom Verge really freaky for example and used it during a sci-fantasy horror one-shot. If such atmosphere depends heavily on the usage of traps there is something wrong.
Not using passives and having players make constant checks every 5seconds just adds to the tediousness. making things more frustrating then they should be. and takes away part of character development/specialization. Then again when going through a dungeon...Within a room or two you can assume that characters switch to active perception and looking out for things. As DM you can then rule to make Spot checks even though they're lower then a passive score. Because passives just do a general look around an area. They might catch a breeze coming from a certain direction as a hint. Which gives the player the chance to decide to describe what they do and on which wall in roleplay fashion. To which the DM then asks for an active spot check to notice the details of where the trap truly is.
When going through a corridor. the bottom half of the walls are covered in detailed braille depictions of a certain scene/culture. There are fire braziers every few steps alternating the side of the wall they're on. Nothing looks out of the ordinary. Cept for the gloomstalker that faintly notices some black liquid on the wall behind one of those flaming braziers. <--- he doesn't know it is truly a trap, he doesnt' know where exactly the trap is nor how it functions. So when another PC runs their hands over the braille art without checking for a trap they accidentally press a small button. Behind the braziers slits open up and gouts of black oil spew out of creating a flame thrower effect. Trap is sprung. Players have to evade the flames and get the hell out of the corridor as the floor is starting to fill with some sort of flammable tar. Describing every few seconds how it rises up and starts to create difficult terrain and slowing the movement speed. Hope this is a clear enough example I've used recently.
Ps. it would've been funnier if the gloomstalker in said example would roleplay how he'd follow the trail and do a spot check. to find that some tiles have different colorastion. The other PC presses the button by accident at that same time causing the slits to open and oil to be blasted in the Gloomstalker's face. Making sure his vision will be obscured for quite some time. And should he also be unlucky to get hit by the flame in the face... well that's leaving a nasty burn scar. Adding flavor to the character.
Id be careful with upping DC or ignoring pass perception without talking to the player about it because their build could have been intentionally geared on the RAW and to find out they are now pretty useless could be annoying.
All posts come with the caveat that I don't know what I'm talking about.
I love passive uses of skills as they speed the game up no end - that said in one game that I am running there are 8 players. Passive skill allows me to tell them what they notice, but they have to still be looking. So if they are randomly walking down the path reading the merchant's price list then they aren't looking around them for danger. They might still hear a wild animal approach but anything that is purely visual they might miss and so roll for it.
Increasing the DC is a bit of a ****** move I think because to get a perception that high at low level would require heavily investing in wisdom, getting expertise and or the feat that adds +5 to passive perception. That player has actively focused on becoming good at that ability to the exclusion of other abilities. Punishing them for that is a little unfair. Someone else also mentioned that yes while they might see the trap, they still have to get around it somehow. Traps and locks may be their thing though, that may be what they love doing. I have a player who is really orientated on that and so I add extra and provide more intricate and detailed ones because that's his area to shine during a session..
There's some dispute both about how passive traits are intended to work, and about how they should work. In general someone taking Expertise (Perception) is saying "Hey, I don't want to ever be surprised by stuff".
My general rule for passive scores is that they're targets -- I will make a check for the trap against a DC of the passive perception of the leader -- but that's not RAW.
I definitely feel that this comment and "meta gaming bullshit" and "***dick?*** move" is directed at me, LOL! That's fine, I only posted RAW examples on how to increase difficulties if you feel it's warranted, it's right there in the rules so, obviously it occurred to the designers.
I can tell you from experience, playing with another PC who has Observant feat making his Passive Perception 22, is Hella Boring. The guy has to be actively doing something else or asleep to not notice anything less than Hard on the DC table.
Other Activities
Characters who turn their attention to other tasks as the group travels are not focused on watching for danger. These characters don’t contribute their passive Wisdom (Perception) scores to the group’s chance of noticing hidden threats. partial quote.
Not really aimed at anyone. I'm also not disagreeing with it being a solution. I'm just saying that it should be laid out to the player and probably with the option for them to change their character.
If they have been spending "resources" [point buy, asi, feats] to get a really good passive perception at the cost of not being good at other things and then you change it unilaterally their charcter looses all power and is now likely to be weaker at the things that you have left untouched.
Id say the same would be true regardless of what it is you change half way through.
All posts come with the caveat that I don't know what I'm talking about.
While I know what you are saying, let me put it to you another way.
If a character was built by a players who's main goal was to have the highest AC possible(this is a common goal), would you just allow him to be virtually untouched by physical combat? Most DM's wouldn't. They would either create something that had a chance to hit the PC or go with an even more dastardly plan, like undermine their whole impenetrable defense concept by spell checking their weak stats.
Now before you say this is also unfair, I use this example because it relates to my own Fighter character. I have Plate, Dual Wield, Crit Immunity, Freedom of Movement, Heavy Armor Master, very good Str, decent Dex and Con. I'm sure you get the picture. To challenge me physically, you need to throw in Giants and other big scary monsters my way. To challenge my average stats of Int, Cha or Wis...it doesn't take much. I am perfectly fine with being spelled up because I trust both my DM and the other players to throw me a lifeline and keep me in the game and relevant.
So, should I have "the talk" to change my character because, as you put it, "If they have been spending "resources" [point buy, asi, feats] to get a really good passive(defenses in my case) perception at the cost of not being good at other things and then you change it unilaterally their charcter looses all power and is now likely to be weaker at the things that you have left untouched"?
I think that's pretty unnecessary. I shouldn't be an untouchable juggernaut all the time but, sometimes I am! That's moderation. In my first response, I said: "Also, it is not unreasonable to set more difficult traps and hazards for the PCs in some cases", that's not changing things unilaterally. That's changing things with moderation and forethought.
I can't take credit for this idea, but I have run with it since I read it. For me, passive skills are only used to oppose active rolls because someone should always be rolling.
"Not all those who wander are lost"
Even if a character has high AC. It doesn't make them virtually untouchable. Flanking and/or Aid/Help rules will grant advantage for enemies to attack. "sacrifice" a creature to knock the PC prone. Allowing others to get close and gain advantage. Combined with other tactics and the multi-attacks that PC will still take plenty of hits. Having such a high AC isn't a big issue since that character will have crappy Int, Wis and/or Charisma. You can easily wound and deal with them if using the tools the game presents. It is not dastardly at all as long as the enemy you put in front of them makes sense to be there. And of course not use them every time.
Cleric at my table. I've let him gain proficiency in heavy armor. because i'm nice like that. With spells and such he can go from 21AC to 23-24. 2 Hobgoblin Iron Fists can deal with him in physical attacks just fine. Just use proper tactics and plenty of their multi-attacks will land. taking him down gradually without him being able to even land a hit in between due to Shadow Jaunt. He got cocky for being "unkillable" for a while. Use that overconfidence against them. Especially since the past they had a fight with an AoE charm effect as lair action. That wiped out almost the entire party. So its isn't as if the player is unaware of the trade off and risks. The decision of how to build and invest in their character is theirs in the end. Let them enjoy that investment in both the pro's and cons.
@texas
I suppose that would depend on the situation. If someone tries to scry and does an active role. Then using the passive perception of the PC to notice it makes sense. especially if you're written it down and don't have to ask the player for the number. Otherwise you'd be giving it away regardless. seeing how most people meta-game whether they try to or not. It makes sense to do it this way.
I have a character who recently picked the Observant feat and I'm still struggling with how to play it without giving every secret every time, but without making the player feel like they wasted a feat.
"Not all those who wander are lost"
I dont think that particularly changes my initial statement of being careful about changing it [and any mechanic] part way through a game.
The AC one both fit in the same type of encouter. Even targeting your weaker stats with spells wouldnt detracted from you still being pretty much untouchable for physical damage. Where as removing/altering perception could take out someone's whole vision of being a scout at the expense of being less effective in combat.
However both seem to agree that depends on the table...
All posts come with the caveat that I don't know what I'm talking about.
You don't. I recommend asking them to take a different feat.
I think I will do this. I really don't want them to waste a feat on something I'm not into from a narrative standpoint.
"Not all those who wander are lost"
Just let them have the feat. If I understand it just lets you lip read. and a +5 to passive perception and passive investigation.
Lip reading can be dealt with easy enough with obvious ways. Telling a player not to take something for these kinds of reasons is such a cheap cop-out.
Having a 20 perception/investigation doesn't meant they see and solve everything. Passive means a very global general view of what is going on. That player will more easily notice that something is going on and find 1 or 2 obvious leads and that is it. When designing an investigation you usually create multiple scenes/environments. With 3-4 clues per location. Ranging from the very obvious that you see upon entering the area. Some moderate clues. And clues that are more obscure and require a closer detailed look. The player with the higher passive will just notice the obvious clue and something that'll draws their eye to the moderate clue. That is all. The rest is still up to roleplaying, further and actual active investigation and putting the pieces together. And in a previous example I already showed that a high passive perception will NOT automatically find the trap and know how to disarm it. They're just aware something is up and find the first clue to finding the trap.
By unnecessarily banning such a feat means you take away the chance for players who want to play Sherlock Holmes type of characters.
The rules for passive checks are dysfunctional enough that you should never permit anything that specifically only applies to passive checks.
I'm not banning it. I am telling them how I intend to play it and allowing them to change feats if they feel my implementation is disappointing.
"Not all those who wander are lost"
you mean how people apply it is dysfunctional. treating it in the similar vain as "taking 10" is just dumb.