Well for one it depends a lot on your vid card and monitor. I think the game as a whole is FAR too dark. Gamma 1.0 should be standard, if my desktop and vid card are already balanced. However for a long time I had to fly at 1.8, and that REALLY screws things up, I can't read green icons against the blue sky. I had to change to a sickly yellow, and can only barely read that (and sure can't read pilot names near me). Lately I'm down to 1.4 or so because I got a faster vid card than I started out with, but I still can't read pilots' names against the super bright gamma-induced sky. Ah1 had MUCh better color balance. Everything is just too far saturated in AH2, so that it hurts my eyes at times.
Problem is if I go down to lower gamma I can't see s***.