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 
aiming down sights? oh, you mean when my eyes develop a massive red crosshair in the centre of my vision and i can actually look up and down?
Hell yeah that's from your special MI6 Training.