For a long time I thought the game was too light at night. Just played build .16, was actually really impressed with how dark it got at night.
Nobody in their right mind would dare walk through a town at midnight, especially when the electricity is out.
The brightness it's currently at is perfect in my opinion. It really makes street-lights and torches useful. Imagine walking through a forest at night, for your torch to flicker and run out. That's what makes Zomboid so damn immersive and fun.
I'd seriously consider keeping the brightness to current levels.