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 
having a mechanic that lowers your FOV and slows the player character down makes for a slower, less movement focused game
Apex Legends is a fast-paced game, but it would be faster, more movement focused game without an ADS system that slows your character down and reduces your FOV
Destiny 2 is a fast-paced game that has weapon perks that exist just so you can move faster while ADSing, but it would be a faster, more movement focused game if it didn’t have the ADS mobility/FOV drawbacks to begin with
Apex is slow as molasses. TItanfall 2 and Tribes 3 are where you need to be if you gotta go fast. Destiny is basically a 1968 Oldsmobile Land Cow Deluxe trying to cough and choke it’s way up a thirty degree grade in the andes by comparison.