Letting a player pick the Light domain for a Cleric of Shar? Death for a Cleric of Lathander? Arcana for Tempus? I think there needs to be a limit to this kind of "creativity" or the gods won't mean much.
It's entirely possible to pick a deity based on the domain powers you want. Why would you also need to be able to make contradictory combinations?
For the sake of multiplayer and keeping the game world intact, I hope the domains / subclasses will be appropriately restricted. Also more intuitive for new players so they don't have to be puzzled by why they can choose the Light subclass for a God of Darkness and then go googling if there is any penalty for that.
