Pretty sure it's just from the different time of day and various cloud/weather systems on Luminous. In FFXV even with a slight change in the the post effects, sky and time of day will have a drastic effect on the hue/colors of the whole game world & objects, some sky conditions giving more muted colors. In the debug build you can change the sky conditions at will.
In the previous dev footage for their new game they showed clear blue skies and everything was bright and green compared to the conditions in the new trailer.