Looking for an interesting discussion, fluff and/or rules references are fine...but no right/wrong derails please. (see those other two threads...
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Set up: A big part of my campaigns were "lower" level characters using the ethereal to get to the deep ethereal, and thus travel to other worlds. You could use the shadow realm similarly.
Then at higher levels, they would astral travel, and eventually with known locations, start teleporting/gating semi-directly.
"We" like the travel / encounter aspect of the planes.
So, long story short (tooooo late!) I replaced the Deep Ethereal, which no longer exists in 5e, with Limbo. No problem so far.
Here's the "fun" part;
Etherealness is a 7th level spell, affects 1 person without up casting. I add the "step away from reality and enter Limbo" part back in. Peachy right? One Person.
Plane Shift is a 7th level spell, affects up to 8 people.
Nobody in their right mind will choose Etherealness (for planar travel). My Faerie Realms and Shadow are also locations in the ethereal, but once again plane shift trumps that.
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I was thinking of reducing the spell level of Etherealness to 5th level, and having it affect up to 8 people. This would put it on the same level as Teleportation Circle.
So for exploration its either the circle for known locations you learned, or etherealness for exploring the cosmos.
Pros/Cons, brilliant ideas I didn't think of, etc?

Set up: A big part of my campaigns were "lower" level characters using the ethereal to get to the deep ethereal, and thus travel to other worlds. You could use the shadow realm similarly.
Then at higher levels, they would astral travel, and eventually with known locations, start teleporting/gating semi-directly.
"We" like the travel / encounter aspect of the planes.
So, long story short (tooooo late!) I replaced the Deep Ethereal, which no longer exists in 5e, with Limbo. No problem so far.
Here's the "fun" part;
Etherealness is a 7th level spell, affects 1 person without up casting. I add the "step away from reality and enter Limbo" part back in. Peachy right? One Person.
Plane Shift is a 7th level spell, affects up to 8 people.
Nobody in their right mind will choose Etherealness (for planar travel). My Faerie Realms and Shadow are also locations in the ethereal, but once again plane shift trumps that.
----------------------------
I was thinking of reducing the spell level of Etherealness to 5th level, and having it affect up to 8 people. This would put it on the same level as Teleportation Circle.
So for exploration its either the circle for known locations you learned, or etherealness for exploring the cosmos.
Pros/Cons, brilliant ideas I didn't think of, etc?