No current patrol zone offers the area, number of enemies, roaming bosses, or events that would go along with this type of space. It is not much like current patrols, and simply beefing up the existing enemies wouldnt be enough. Nothing like halo, so I wont adress that. This would be an entirely new type of space. Only gets easier with a new cap, and at that point, new areas open up to explore. In the same manner. Its about the immersion into the enemy controlled areas, exploring with the sense that you could be in over your head if you arent careful, Bringing teams to explore the furthers and darkest corners...that'd be fun even after it gets easy enough for casuals to play.

So a "no ghost zone" like some activities like raids / strikes do but added in the wilderness? sounds interesting and some maps can benefit from that, like the lost sectors, making them bigger and to connect to other areas or even other lost sectors I mean a real -blam!-in labyrinth that would be awesome

Yeah kind of like the EDZ where alot of lost sectors connect two zones of the map together. It would possibly be cool to activate forts and as long as you dont go to orbit you can spawn there. Having the area be a darkness zone would work, but not on the forts or main spawn

The purpose of the forts should be broader than just a mere spawn point in a darkness zone, maybe a unique npc area? (like the corsair camps in the dreaming city but more...interactive)

Check my OP, forts are where you summon an enemy event, based on your fireteam size. Once you capture it...you can spawn there.