Instead why dont they use the system dayz does? It determines whatever can be seen at night from player pov, and anything that wouldnt be able to be see is turned pitch black. So upping gamma or monitor brightness helps li5tle to non.
Turns out that's harder to do than you'd think. The devs were looking at the solution Crysis uses: Anything that's too dark to be seen is covered by a very dim pixel fog that's entirely invisible at normal brightness; if you max out gamma to see in the dark, the pixel fog pops into view and obscures your vision. This is likewise harder to do properly, since the game has to constantly recalculate what is and isn't visible and fog out parts of the frame.