By no mean I'm a game designer, but I've read small complains there and there about ambushes not being really impactfull, with just a small amount of zombies attacking you.

Wouldnt it be cool that when an ambush triggers, the map goes full dark just like during a "lights out" condition? of course with an increase of ennemies spawning, it would really create an "oh shit" moment. I've seen a lot of people being fan of the "lights out" but correct me if I'm wrong, it only happens in auric damnation (maybe regular missions too? idk) and it would make the flashlights a bit more useful and also teach new players about fighting in total darkness