I prefixed and overwrote the environment map texture = "dz\data\data\env_land_co.paa"; just as a test and wanted to share with you the results.

The windows are what the vanilla environment map looks like at night. It appears to be emissive (what you see is the top of the environment map where it's light blue) as it's still very much visual despite being in a non lit area.

This is what a fully black environment map looks like.

As you can see it looks way better because the windows are not glowing unrealistically.

Here's another example of how great it looks.

With the new lighting changes + the popularity of lighting adjustments like @Lad 's lighting overhaul, this became much more obvious.

Also, a black environment map is by no means the solution. However, I don't think it's possible for us modders to fix it otherwise, just thought it'd be nice to show the fruit of labor.