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 
i know ive posted a lot in this thread but i have a rant. generally i think its weird how all shooter games have very similar controls these days, bring back lock on aiming like in old skool SOCOM and PS2 half life and red faction imo. or rather instead of bringing back, come up with new stuff or new spins on old stuff. i'm absolutely exhausted and sick of playing 'COD but x genre' or 'Quake but x genre' games. i think lock-on aiming systems have a lot of potential and might even be closer to real life instinctual aiming in CQB situations. i also think more games should have a difference between 'weapon up' and 'weapon down' postures with implications for mobility and other gameplay systems. the metal gear series touches on some of this but nothing goes as far as i want. like compare how people move in any given FPS or TPS game and then watch a decent war movie like saving private ryan or full metal jacket, and notice how much more agile real people seem. diving and rolling and crawling and running hunched over. clumsy but fluid, not mechanical and floaty or glide-y. we are so so far from having that in any videogame, and im not convinced its purely an issue of controls or input. so many games animate the player characters like they are a drone more than a person or even a physically existing android.
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
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.
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.
But that would require writing new systems and handling more interactions instead of reusing templates and old code.
Games are meant to make profits and the more money you spend on slop that gamers are going to buy anyway, the less profit you make.
Many games now have systems called aim assist and bullet magnetism. There's also some sticky-aim thing but i can't recall hwat it's called
aim assist nudges you crosshair towards enemies
bullet magnetism causes bulletsn or at least the hurt box attached to the bullet graphics, to fly towards enemies
and the sticky aiming thing makes you aim "stick" slightly when you go over an enemy, meaning you need to move it more than usual to keep going.
If done well the player gets a great deal of help from the computer to be gooder at shooting stuff, but it's subtle enough that you either don't notice, or can easily suspend disbelief and ignore it.