This is the feature I would love to have.
White balance settings
Contrast settings
maybe even some Color Control
Not everyone's eyes see the same color or prefer the same settings, some are bothered by higher contrast, some are bothered by lower contrast, some like a bright white screen, some like a warmer screen.
these control are most likely available, just not to the user, they could leave everything the same and on the brightness screen have a toggle for advance controls, and a toggle to return to default settings.
Simple, and would probably clear up 50% of return issues with people wanting different white balance.