This is an AMAZING idea!!!! When I played EQ I half expected there to be a Plane of Darkness or Shadows where you go in and can't see anything. And only a Paladin or Cleric can shine light and guide a party through. It'll be like the "upside down" place in Stranger Things which was taken from the Shadow Plane in D&D.
This could even be a great addition for a Halloween patch and the portal to the place only opens up when there's a certain alighnment of stars (which will be every October in real-life).
You can even make "darkness" be an environmental condition just like Heat and Cold where you will start to lose your SANITY the longer you are in the darkness without a light!!!! The ideas are endless!!
Lets see what the designers think about this.
I'm a fan of having HORDES of monsters just outside the barrier of the light. And you can constantly hear them all around you. Sometimes they keep "testing" the barrier and you hear them screech in pain and you smell burning. This is where you have to make sure that the LIGHT DOESN'T GO OUT or you are screwed.
Right? I remember when I played DOOM (2003) for the first time on my friend's gaming computer. It was dark in his room. And in that game your flashlight kept going off and on. My heart was POUNDING. He came into the room real quick to get something and just him opening the door suddenly made me jump and I knocked over his monitor and fell over on the chair......
That's the feeling and experience I think about when I think about this idea. But you are right, there are so many ways you can run with this and it will be gold.