Visible RGB values for hair-color sliders would rock my world if possible.
Visible character proportion numbers would be equally awesome.
Delete character completely, clearing the character slot (instead of just remaking).
Disable the automatic bypass of the boss-teleporter confirmation dialogue, or make it toggleable. I know it's pretty easily avoidable, but I still think it's potentially dangerous. Perhaps by extension, apply the same behavior to area teleporters (that is automatic/toggleable).