I was just thinking about how annoying it is to hang out in the wilderness without a light source and not being able to function at all. My suggestion is not the old style night vision that orcs had where they could see at night like it was day.
My suggestion is that after 5-10 minutes of darkness our pc's eyes should adjust to darkness (with an echo) allowing our players to see in the dark within the room they are in without a light source. This night vision should last while moving rooms until a light source is placed in the same room as the pc to ruin the night vision.
Seems like a difficult thing to code maybe? But I doubt anyone would actually not want this.