BF109 - Can't we just have the gunsight in the middle?

[Jaws2002]

The best way to understand what Lixma is trying to say, is to just go to a gun range, or gun store, and try it yourself with a rifle with reflex sight (like the eotech).
Just bring the rifle in front of your eye and aim at a distant object while keeping both eyes open.
The reticule in the reflex sight is projected far away in front and actls like a front sight that is way far in front of you, so the focal distance for the dot is really close to the focal distance for the target.
If you aim with both eyes open your dominant eye will take over and impose the reticule visible with one eye over the entire image. Of course your dominant eye has to be in line with the center of the sight, but you still have a lot more room to play compared to irons.

But in game i think is really hard to implement this. The image with he reticule floating over everything is not exatly right. Human eye will simply blur the glass of the sight when it concentrate on the distant target and reticule.