I don't play PvP, but from a story perspective why hasn't Shaxx brought in a "no light" version of the crucible? Xivu Arath has, across several seasons, shown an ability to deny us our abilities, and the Crucible's main lore purpose is to train guardians to handle high intensity combat scenarios. Why wouldn't Shaxx have a new mode to help less skilled guardians prepare for these sort of encounters? Gameplay wise I can imagine that it hasn't happened because a large proportion of the PvP community would not want to engage with it because they enjoy the space magic aspect of this game. PvP always suffers when the population drops significantly, in any game.