Never get so many layers deep in the conspiracy you outdo the writers, I don't think they've thought through it on this many levels. I'm not even sure the light and void will play that big of a role this expansion. Though said, I do think that "light save my soul" moment cleaving Uther's soul shows a power we didn't know those forces had, and an interesting opposition between Light and Death. Does the Light have its own Shadowlands realm? It would seem not, if Uther's rescued soul wound up in Bastion. Unless that is the light realm. In which case, what's the Shadow Realm?
Unless...
We do know they love stealing ideas. :P