To be clear, my feedback is not about aesthetics but accessibility. I've never tinkered with the shaders, so I don't know whether adjusting the white on my end would also adjust the chat color (meaning it would not achieve the contrast necessary to make text more legible). I do know that other areas of the module (e.g. Krofburg) are already so dark that even for a PC with darkvision navigating is an exercise in frustration. Consequently, I'm unlikely to want to optimize globally based on an area that I have spent almost no time playing in and would not expect to do so except for the occasional event.
I think the ballroom *looks* fine. Quite a lot of Dementlieu--as I remarked to Dread about the lift in the theatre only two nights ago--is imaginative and visually pleasing. But the combination of color and area size for the dance floor as a practical matter (for my eyes at least) is problematic.