I wrote up a thingy detailing the gist of some of Halo 3's graphical choices, what they mean, and how they come together. Some may find it interesting. On the whole, I think Halo 3's graphical makeup is pretty fascinating, in how much it overshoots and undershoots on various things in the generational leap, and how it nonetheless comes together into a product that a lot of people think looks pretty good.
https://halotupolev.wordpress.com/2016/04/21/sixth-and-eighth-the-graphics-of-halo-3/
https://halotupolev.wordpress.com/2016/04/21/sixth-and-eighth-the-graphics-of-halo-3/