There's armor option in difficulty settings right? If you want to simulate armor just make it so people can turn it on on every level of difficulty. So it will be up to server hosts if they want it on or off. Armor is not a valid reason to tweak damage.
So in milsim-like game there's a reason for .45 cal gun to hit like 4 times in the chest to put down a man? Is this CoD or something? -69% damage (from 4500 to 1389) is not even overboard, it's total overkill.
Agree with -=seany=- and OMAC on most points. I'm fine with dark nights in Chernarus but when it "dark" even at day... let's just say it sux. What's more unnatural is that when you are trying to avoid looking at skies lighting seems fine. When you get some sky on your screen even if there's no sun on it it becomes darker and very frustrating to play. Hope you manage to tweak lighting settings right as it was just fine few beta patches ago.