I wonder, what if bungie is trying to break away from the associations of light and dark? Generally light is seen as a good thing that gives hope, and dark as substantially evil and fearful. If the Traveller were to turn out evil, what if the light is evil, and the dark is good? After our guardian is revived from the dead, what if we just automatically assume that light=good and we have our associations entirely backwards due to human connotations?