I haven't bothered much about panel colors so far, but what somehow bothers me more than the panel colors is the way each module looks so different from the other.
Even if you get all black modules, they still look different in style. Some have a shiny finish, while others are simply matte black; some appear "blacker" than others; some panels appear clean and minimalistic, while others appear busy and a little crazy; then you have gold on black and white on black trends too; don't even get started with knobs, as they come in all sizes and colors too.
Eurorack looks busy and intimidating, and I totally understand those who replace the original panels and knobs to make the instrument look homogenous, more clear, and more approachable. Maybe going all-in on black panels is a way to bring some order to this madness.