Don’t think i do agree with that. There are a lot of things you can do, which puts the player in a position they do not want to be in, or want to deal with.
For example, you could have included a new type of enemy that can grab the enemy and appear out of nowhere with little to no warning. Like say you have a Demon tentacle appear out of a wall, that grabs the player. This would pose a serious threat on higher difficulties. If you then hint of an area where this could happen, by plastering increased nurgle infection in an area… then you would have players be on edge when they enter this area. The unknownable nature of the threat combined with the forewarning of being in such an area, would be enough to cause players to be weary, worried and even dreading the encounter, despite the ability of having weapons that can deal with it.
In a similar fashion this could then go hand in hand with a new monstrosity… like say an amped up Chaos Spawn. Give it a portal animation, and have the Operatives encounter it a few times. Have it’s tentacles be the attacker in the Dark… and give it, much like weakened monstrosities a chance to spawn whenever a special or elite is generated by the game. But when it spawns it does not get the Healthbar shown, as customary of Monstrosities nor does it play the Monstrosity BGM. This way you can have it suddenly spring up out of a horde of Crushers or whatever, completely taking the Player by surprise. Combine that with harassing the player with the Tentacles… and you created a very tense situation that the Player will not enjoy being in.
Then let the Monstrosity “portal” away, when its health gets to a threshold… and put it into a large open area at the end of the mission, so the player gets to murder it.
For example they could have repurposed Hab Dryko for this. Remove the tree in the center of the end arena… turn it into a big boss fight. Buff its HP (this is where it gets an HP bar, maybe make it a 3 stage fight with 3 Health Bars and it runs away after you deplete one of them, to ambush the operatives that fight the horde in the mean time), make tentacles appear out of the ground and not just walls… and spawn in a Horde, much like with Assassination Targets.
The maze like level of Hab Dryko could then also be used to allow for the abduction of players. Instead of the Chaos Spawn eating someone, it takes you for a ride like the Beast of Nurgle does.
And while tentacles might be easily destroyed, much like Hounds… the fact that you can be dragged off position, the lack of information on the enemy, its elusive nature… and high threat combined with the low visibility would make the whole thing a very dreadful situation.
It would be very much a “Terror in the Dark” situation.
To make the players engage with this despite of that, you give better rewards than a couple Plaststeel (i mean when we play Damnation we go home with 800ish plasteel per mission, so 4k plasteel as reward is really not that much) and whatnot, which a lot of people are swimming in. Give people something they really want as a reward… and you’d have the Player base engage with your content and loath every second of it, because the Dark Hab is a place of Terror and you have a genuine reason to be afraid of the Dark, because at any given moment a Chaos Spawn could pounce you. Bonus points if you give it a new paint coat and make it look like black slime to be extra hard to spot in the Dark.