Great work with the mod pydon, keep it up. I've spent some time now running Crysis with it and I have to say I like the colder washed out look over the original. Lighting and Shadows at dawn and dusk are a huge improvement IMHO over the original. I have to disagree with some of the other members here as I prefer how the background is hazy and washed out. The mountains you see in the distance often represent the physical limits of the map itself and to me don't look all that realistic. By obscuring them the short comings in the rendering of these mountains is less apparent, opinions vary of course.
Dark shadow brings up a valid point with the fog, in places it is perhaps a bit excessive. You've been using the Recovery level to test the mod the irony being that I would like to perhaps see more fog in that level. The Awakening level on the other hand could do with a compromise between the original and the mod, see the attached images as a reference.
If there is one thing that I don't like about the mod, its that the night time scenes during the second part of the Relic level where Nomad exfils the excavation site is just too dark. I agree with you that the original wasn't dark enough, however as there is a full moon some ambient light would be a big improvement. Having said that as I pointed out at the start I'm very impressed with the mod and I'm looking forward to see what direction you take it.