The point is looking at the sun should literally be the brightest thing possible you can do. Why isn't it WHITE? Here's an example of blinding sun:
It's white, if in-game the color of the sun is only light grey, what exactly would constitute something bright enough to be white?
That picture is horribly overexposed. It's near sunrise or sunset, and it shouldn't look anything like that (in a decent photo). As for the eye, the eye has far greater dynamic range than most (all?) cameras.
Regardless, it's a game, and you make things look real, but you also want it to look decent and this mod look great to my eyes. If you want a mod to look like that picture above, make it, but I promise you that few people want GTA to look that bad.