The colorblind settings are hilarious since they seem to focus more on can you see it for the extremely colorblind rather than doing something to compensate. I have a red deficiency, so the reds tend to lean toward the black and I had to switch to the green-blind setting to make any of the defaults make sense to me. I tend to give it a pass though since there's a custom option and I just set the enemy to be more of a burnt orange.
As for the sights... I had serious problems seeing some of the red dots and other holo sights. Either the color needs to be an option in the colorblind settings, or you should at least be able to select red, green, or blue options since those are now commonly available on the real market. I even have a green laser on my pistol at home because the red wouldn't show up well enough unless I maxed out the power setting.