Personally, I'm not against the focus because IRL we perceive better at long range than ingame (except for myopic who broke their glasses).
IRL, I'm a shooter with the swiss assault rifle at 300 m. I take around 1 to 2 secondes before shooting with a good sight (alignment) on the target bellow and I can easily hit the 3 and often the 4. But... I'm quit, lying down, not cold, not out of breath... In very good condition.
Breath:
The breath is for me the most important condition, without a good control you can't hit what you want at this distance. So, after a furious run, comptetely out of breath, it is virtually impossible to aim correctly before you stop breathing. In some cases, it's really hard ! And you need to wait a little or you can only stop your breath during 1 to 2 sec (for me IRL it's the time I need to aim correctly so I have great difficulty to fire correctly).
>My solution ingame: when out of breath, only a short time focus and stop breathing or waiting 5 to 10 sec before we can stop breathing for the same time.
Alignment (good sight):
Yes, a good trained soldier can fire quickly with a relative good sight. I fire at 300 m and ingame, the most of the case, I fire from 50 to 150 m when it isn't CQC. So, another yes, it's easy to hit someone at this "short" distance compared with 300 m. But... yes, always but... I'm not precise than ingame because my alignment isn't the same betwen each shoot if I don't take time to aim correctly (relative what I saied, at this range I take the half of time to aim so 1/2 to 1 sec). But, with all my goodwill... my alignment isn't precise than ingame. And, when I fire IRL, I'm not afraid, I'm always in good condition. It's sure with fear, excitement on the battle, it's a different story.
>My first solution ingame: we need to align when we hit the focus key, to obtain a good sight like in real.
>My second solution ingame (but not possible): we need to align with a TrackIR or Freetrack system (impossible because there is so less players with that)
Yes, it's a little to easy ingame to kill someone like we do but it isn't a problem for me, it's still a game.
So for me, focus yes because often it help me to be sure if is an ennemy or not... but with the conditions described above, it would be for me a dream.
PS: sorry for my bad english (written quickly)