It’s not necessary as well as when Darkness is a mission type, not an environment. However, i can have an idea to iA to make Darkness a bit unique and realistic as well. These are two ideas i can give to iA to make your dream come true:
When you zoom out to see the map, you can see that stars systems are not that far to each other. However, in the universe, there are many voids without a black hole, both inside and outside the galaxy. Instead, voids have stars system with much less dense. iA can expand the map with some void in edges and corners, with a much less density of stars system. Those place can be much darker due to the density of star systems, so Darkness missions at this place can be appeared more than in every place.
New object: Nebula (With a continue-forming star core inside): Inside the nebula, light have a hard way to go. Although nebula have a better vacuum than the best vacuum people can make in lab, light still have a hard way to go. The star inside the nebula so are very hard to see, so planets around them can have Darkness missions only as what you want.
Or maybe iA can create Rogue planets, planets without a star to have a trajectory around. Thost planets are barely visible due to the darkness it has. Those rogue planets can fly aimlessly on the map, so finding them maybe a little tricky.
