The issue with the sights is that even if you are aiming at people or buildings or the ground the sight picture is still pretty hard to see, the reticle will often blend in with character models armor, or in the case of the Executioner it will blend in with the shield since they are both blue, and shields are visible when on. And the thing about weapon optics, is that they should be very visible in most situations, in this case they are difficult to see in most situations, and unless I'm mistaken, Frontier doesn't seem to be aware of the issue. I tried posting this problem on the issue tracker and posted it on reddit asking the community to try and push this issue up, but people didn't really respond to it, so I have no idea if many people even see this as an issue.