I've said this in the past when people say it's too bright outside when there's a full moon in the sky... I've lived in the country almost my entire life. I've seen very dark nights because there's no lights anywhere around to brighten the sky. But when there's a full moon in the sky? It isn't dark. It's dim at best. Not really any different from the game on default brightness, and certainly not darker than the game with brightness turned down.
The issue some people have is that they want it to be "scary". This game is not exactly intended to be "scary". There are so much jokes mixed into the game, if you know where to look for them and understand where they joke comes from, that "scary" really doesn't apply to this game. If you're looking for real horror, this isn't really the best game for you. The best this game can offer in that regard (or ever will) are jump scares on rare occasions. Lighting won't change that.
Consider a zombie coming up behind you when you can't see them and don't hear them and they attack you. What is your response? Run in fear? No ... unless it's something like a dire wolf, maybe.
You turn around and kill it. A zombie coming up behind you and surprising you is far more "invisible" than a zombie coming up in front of you when it is dark and hard to see because you'll still see the zombie in front of you even if you can't see it until it is a few meters away. A zombie behind you can't be seen at all until you turn around. Yet even so, are you really scared because you didn't see it? Of course not. This isn't that kind of a game.
People adjust brightness all the time in games. It's hardly a difficult thing to do and pretty much any gamer knows how to do that unless they only play casual games where brightness isn't an option. And in that case, they aren't likely to be complaining about the darkness on this game anyhow. Yes, if the lowest setting isn't dark enough for you, then you're either stuck or have to use a mod. But that's always true unless there's a brightness setting that has entirely zero light and you can't see inches in front of your face. So there really isn't a problem with telling people they can adjust their brightness. As I said earlier, it might be useful to have the brightness setting pop up the first time someone plays the game like other games do for gamma, but that's really just a slight convenience and not really necessary.
As far as adjusting defaults? First, that only applies to new players or new installs after a complete wipe of settings or clicking the default settings button because they should never change our own settings after we set things the way we like. So everyone here who is complaining about brightness wouldn't see any improvement if they change the defaults since they are already using their own settings, which wouldn't be changed. So the impact of that kind of change would be limited.
What they could do that would be of more benefit beyond the brightness popup when first loading the game after an install would be to have a tooltip on the brightness setting that clearly explains how it works. That at least lets people understand that it won't change daytime brightness and then maybe they'll actually change the setting.
In the end, they can change defaults and it won't matter to any current players because it won't impact your own settings. So I couldn't care less if they do that. Go for it. But will it really make any difference? Probably not much. If people can't already figure out how to change their brightness if they want it darker, then they are likely going to be complaining about all the other options that are available and not set to how they personally want them.
And, for reference, I have my brightness at 20. It does look good to me. But I didn't get upset about brightness... I just changed it.
