In terms of gameplay mechanics, old school zoom aiming achieves the same thing as ADS. Is getting to press your nose against virtual firearms really that important in a game about shooting werevolves and vampires?
I blame this on the proliferation of Call of Duty over traditional scifi and fantasy shooter franchises. You can fucking ADS on an assault rifle in Halo now 
How would you make movement that complicated work on a controller/mouse and keyboard unless you turned it into some kind of contextual animated thing
People also tend to like the smooth glidey video game movement. Many turn off any kind of head bobbing because it gives them motion sickness and they find realistic or physics-driven movement clumsy and annoying
i like contextual animations, you could also use a bunch of contextual radial menus for stuff that isn't immediately necessary to free up controls. mostly contextual animations could be better i think, they only even try that approach in 3rd person games.
for camera bob and motion sickness, i think the camera in FP could just not be directly physically attached to the player model, or have a zone inside the head (which is not rendered like in ARMA or perhaps behind the camera) in which the camera can move freely to stabilize itself. or a combination of approaches. i think battlefield games usually have realistic looking run animations sometimes by just rendering a different model in first person with just legs and putting the camera in the chest (arms and weapon drawn on the HUD layer). playing GTA4 with first person mods didn't give me any motion sickness at least except maybe during car crashes. animations don't necessarily have to be physics based either, handmade or edited motion capture animations done well can have similar visual effects.
You do a contextual animated thing. Games nowadays can blend animations to alow you character to move much more dynamically, shift between poses while doing other actions, interact more distinctly with the ground or objects instead of being a capsule attached to a plane. Hd2 does it quite well.