Something that a Forge mod with equivalent functionality (Hardcore Darkness) does which I would love to see in this one is the ability to configure the light levels more: i.e. config options such as:
New_Moon_Light=00.0-16.0
Waxing_Moon_Light=00.0-16.0
Waning_Moon_Light=00.0-16.0
Full_Moon_Light=00.0-16.0
Min_Depths_Light=00.0-16.0

Not sure how tough this is to add with how this mod does things but it'd be nice to see in a future version!

I also +1 this, please Grondag

Pretty sure all of this is doable within a shader. Just make a shader for it.

I added a minimum darkness config to the Total Darkness forge mod here: Tfarcenim#3

It was pretty easy and made the mod much more usable for me. Not sure how similar the code structure is to this mod, but if you could implement something like that, I think that one config option would meet 90% of this need.

+1