Background
I am DMing Curse Of Stradh - and there is a lot of Fog in Barovia. The party have characters with and without dark-vision. I am not really happy with how light, darkness and obscurement work with the blinded condition, nor with how Fog-Cloud (L1) and Darkness (L2) spells seem to work and how little difference there is between them in 5E RAW. I would expect them to do more, and Darkness to be stronger than Fog-Cloud since it is L2.
I would like feedback on some house rules I am considering. Specifically if there are some game-braking problems or better solutions.
Concerns
1. A heavily obscured area blocks vision and effectively makes you suffer from blindness condition if looking into it. This seems reasonable until you realize this means you cannot see through normal darkness and see a guard with a torch, nor the moon and stars.
Vision and Light RAW with errata
A heavily obscured area--such as darkness, opaque fog, or dense foliage--blocks vision entirely. A creature effectively suffers from the blinded condition when trying to see something in that area."
Blinded RAW
A blinded creature can’t see and automatically fails any ability check that requires sight. Attack rolls against the creature have advantage, and the creature’s attack rolls have disadvantage.
Darkness RAW
Darkness creates a heavily obscured area.
2. The fact that two fighters in a dark cellar has both advantage and disadvantage (canceling each other as per Sage Advice), seemed odd but acceptable. That is until I considered Darkness and Fog Cloud spells.
All else being the same, what is the point of casting the spell? I can attack and be attacked normally, or waste an action and 2nd level spell slot to cast darkness, and then we can attack each other with advantage and disadvantage canceling out. It makes no difference if I step out of darkness, attack, and then back in, or toggle Darkness on and off by covering a coin with Darkness. What will Fog Cloud and Darkness spell achieve?
Admittedly if I have disadvantage or enemy has advantage already, or I am being targeted by "a target you can see" spell Darkness will help me remove advantage of disadvantage for everyone, but that is rather situational - Blur or Mirror Image (Shatter?) seem much better than Darkness for a second level spell slot.
(Special circumstances like having devil sight or Blind fighter feat obviously change things)
3. If I am in a heavily obscured area (Fog, Foliage) I am effectively blinded. That may be true for someone a bit of a distance away, but what kind of fog or heavy smoke makes me unable to realize someone is standing right beside me? They may find it easier to hide, but even the heaviest fog is not the same as wearing a blindfold at short distances.
RAW Vision and Light
A given area might be lightly or heavily obscured. In a lightly obscured area, such as dim light, patchy fog, or moderate foliage, creatures have disadvantage on Wisdom (Perception) checks that rely on sight.
A heavily obscured area--such as darkness, opaque fog, or dense foliage--blocks vision entirely. A creature effectively suffers from the blinded condition when trying to see something in that area.
The presence or absence of light in an environment creates three categories of illumination: bright light, dim light, and darkness.
Bright light lets most creatures see normally. Even gloomy days provide bright light, as do torches, lanterns, fires, and other sources of illumination within a specific radius.
Dim light, also called shadows, creates a lightly obscured area. An area of dim light is usually a boundary between a source of bright light, such as a torch, and surrounding darkness. The soft light of twilight and dawn also counts as dim light. A particularly brilliant full moon might bathe the land in dim light.
Darkness creates a heavily obscured area. Characters face darkness outdoors at night (even most moonlit nights), within the confines of an unlit dungeon or a subterranean vault, or in an area of magical darkness.
4. I find the difference between Dark-Vision and Non-Darkvision characters is a bit OPed and awkward, even if you remember that dim-light gives disadvantage on perception. If the human or halfling rogue carry a torch no one will be stealth-ing a lot, not even all the other races with dark-vision. So either no one can sneak well or we give everyone dark-vision with gear if needed. Neither seem much fun. If everyone has dark-vision we just cancelled darkness. And if you have ever been in the woods at night far from civilizations lights, you know how spooky that is. And I want things that go bump in the night to be scary.
House-rules I am considering
H1. Add to the blinded condition that you only get advantage if you can see (or something similar) blinded target.
A blinded creature can’t see and automatically fails any ability check that requires sight.
if you can see it (or something equivalent like echolocation blindsight), your
attack rolls against the creature have advantage. The creature’s attack rolls have disadvantage.
This fixes Darkness and Fog cloud not doing a lot. If you hide in area of effect you and your enemy has disadvantage. You can step out and attack with neither advantage of disadvantage (or turn Darkness on/off by covering it).
(After having this idea I discovered others did too, but that does not make it bad https://www.youtube.com/watch?v=ALhcjHnFHW8&t=663s)
H2 Switch cause and effect of light and obscurement. I want to fix it so we can see through normal darkness and see campfires, the moon and stars at night. I also want to make fog in Barovia a bit more of a level playing field between regular vision and dark-vision characters and get that feeling of "something in the fog is sneaking up on us". I also want there to be a difference in effect between the Darkness spell and the Fog Cloud spell.
Bright light: Everyone sees normally
Dim light: Creatures have disadvantage on Wisdom (Perception) checks that rely on sight (FKA Lightly Obscured).
Darkness: A creature effectively suffers from the blinded condition when trying to see something in that area. You need to pick square to attack with disadvantage. Note It does NOT block light/vision, illuminated not-in-darkness things are visible from darkness or beyond.
Treat a lightly obscured area such as patchy fog, or moderate foliage, like Dim Light
Treat a heavily obscured area such as opaque fog, or dense foliage, like Dim light within 5 feet and Darkness past 5 feet. Past 5 feet it blocks vision, including dark-vision, entirely.*
Now the rogue in the (non magical) darkness can see and attack the guard carrying the touch, in this case with advantage since guard is effectively blinded trying to see rogue in darkness beyond the light. And we have a moon and stars again - that should make the lycanthropes happy
H3 Dark-Vision
Dark-Vision treats darkness like Dim Light for 60 (or 120) feet. Past 5 feet in the monochromatic dim light you have disadvantage on attacks (but you do not need to guess square like you may have to if blinded - you can see there is something, but not well). Note heavy obscured blocks dark-vision.
Now Darkvision is less OP compared to regular vision, but rewards sneaking up on someone and shanking them, not just shooting them down from the dark, and once a fight starts dark-visioned archers may hang back but like the illumination their humans friends cast on their foes, granting them advantage rather than disadvantage shooting from the dark.
H4 Darkness Spell: Some feel that RAW implies you can see out of and through Darkness spell area since it only says dark vision cannot, not regular vision. I was tempted to use this to make the spell do something under RAW erattaed Blindness rules. However, that would grant an attacker in darkness advantage against an unsuspecting foe that cannot see him, while also having foe have disadvantage - that seems as strong as 2nd level Blindness spell but for a mobile area that last longer and has no save. Since blindness rule change makes Darkness Spell "work" again, lets be specific and say it blocks light, normal vision, and darkvision. Maybe it is an area of anti-photons that magically "eats" all light.
Magical darkness spreads from a point you choose within range to fill a 15-foot-radius sphere for the duration. The darkness spreads around corners.
It blocks light, normal vision, and dark vision (replaces "creature with darkvision can’t see through this darkness")
and nonmagical light can’t illuminate it. If the point you choose is on an object you are holding or one that isn’t being worn or carried, the darkness emanates from the object and moves with it. Completely covering the source of the darkness with an opaque object, such as a bowl or a helm, blocks the darkness. If any of this spell’s area overlaps with an area of light created by a spell of 2nd level or lower, the spell that created the light is dispelled.
