sooo..... the only real X1.0 its the iron sight?

It's not really about being true x1, but being parallax free. The way a variable power scope works prevents it from being parallax free, even if it is a true 1x (which are rare).

This is untrue, the front sight would not appear blurry in 1x mode. Parallax is to do with the appearance of the reticle depending on the viewing plane. A parallax free optic uses projection methods to make the reticle move as little as possible in relation to the target when being viewed through the optic off-center. The issue 1x-Nx optics have is that in 1x mode is that the user must look directly through the optic as they would with a magnifying optic, otherwise they will experience scope shadow and a potentially misaligned reticle.

Example:
http://www.ar15.com/archive/topic.html?b=3&f=18&t=454478

Parallax free and depth of field have nothing to do with each other. Neither is the sight "co witnessed" with the Ironsights.

The engine cannot do DOF blur very well, and to co-witness a sight with the ironsights mean that point of aim, point of impact is identical when looking through either optics or irons.

InstaGoat: no. Co-witness in general only refers to the ability to use the BUIS through the optic. Absolute co-witness is what you describe, where the reticle of the optics rests on top of the BUIS when you use either one. A 1/3 co-witness is the one used in ArmA 3, where the BUIS are below the typical line of aim.

Mass closing ancient tickets with no activity for > 12 months; assume fixed or too trivial.

If this issue is still relevant in current dev build, please re-post.