Umm, I've always thought that all Id games (except mayve Wolfenstein) have a very strong survival of the fittest undercurrent. It's not something you can accurately describe, rather all the small, unrelated elements of the game that give it its "feel".
It starts with the name "Id" Software, the Id being the part of our mind where the PRIMAL impulses come from, that is exactly how Id games are, there is something primal and savage in them, done in the simplest way possible. You kill or you die. The fact that in Doom, no one ever talks and the only vocalizations are grunts and screams of pain gives the game a lot of character in my opinion. Of course, many games do this but Doom and all 3 Quakes do it in a completely honest and unpretentious way. Kill or be killed, without any bullshit.
Even the names are monosyllabic words that describe intense human emotions or in the case of Doom, a complete and irrevocable sentence. RAGE, DOOM, QUAKE, there is something final, primal and decisive about what these titles inspire.
There is nothing mysterious about the demons, they have one goal only and that is to smash you into putrid piles of gibs. One thing I REALLY disliked about Doom 3 is that when monsters spawn, there is a one second roar animation. That is a complete fuckup because not only does it make the monsters vulnerable for one second but ironically, they also make them less scary. I really hate cutscenes where a demon senses you and slowly turns around. They instead should be very reactive and jump at you the very moment they see you.
Now of course, the way humans deal with this could lead to interesting conflicts, I agree, but it should not be the main part of the game. It should be optional, for those who just want to play the game to kill stuff.
I really like what they've done in Wolfenstein but I'm not sure if it would work in Doom. While Nazis are evil, they are in the end still humans who feel, and this is what separates Wolfenstein from QUAKE and DOOM and this is why I think Wolfenstein would indeed benefit from a story. The monsters in Doom should not have any emotions whatsoever besides rage and bloodlust, it would take away everything I love about them.