I think it's pretty realistic I mean if you're outside of a city at night you really can't see anything, unless you have a lot of moonlight. I get why they made it brighter in DayZ (as NVGs aren't common and you usually spend a lot of time at night) but I like that they keep the nights black in Arma.
Just because it is an inconvenience that you can't see at night on ARMA without NVDs certainly doesn't mean it isn't realistic. Out in the wilderness with very little light pollution it is hard to function in a combat environment; even with NVDs sometimes too if they don't have any light to intensify. It is v hard to function out of the game in pitch black.
Moving at night is a dick but gives us the advantage over the enemy without the same technology capabilities.. crazily emphasized by this video haha!