A few push maps, for reasons unknown, have outrageous fog colors. The dark maps are entirely too dark. I usually prefer to play on green team but with the dark blue/black fog I cant even see what I'm shooting at. If my skins didn't have a grey strip on the face I wouldn't even see a blue player. And have you ever tried hitting a tinny dark grey strip on a blue/black fog background at 180 blocks away? It might not be impossible or incredibly hard but on push when you're taking on 8 guys at one time? Might as well put on a blindfold and try to play arena.
That does sound like it gives the other team a significant advantage.
Your post does bring up a cool new dynamic. Since the color of the fog benefits the same color team. Then if the fog color changed to the losing teams color, that would give the losing team an advantage to be able to catch up.
Example: Blue is Winning so the fog turns green to help the losing Green Team. Blue is losing, then fog turns blue.
I understand that players are able to change the color of team by editing their game files. Changing enemy characters to a very bright color that contrasts with the fog might be a solution, but not the best.
I agree that the fog and other terrain colors in the map plays a factor in how well a player can be camouflaged. Often, I choose which team I will join based on how well the uniform well blend into the terrain.