So what reason is there currently to go back to either of those raids if you've gotten all of the equipment? You keep people playing by giving them a reason to play the activities. The chance for Etheric Light could be the same chance that you have to get an exotic out of the Gorgon's chest. On a good week, you MIGHT get 1-2 from the raids. Why give 2+ from Trials of Osiris, but not have a chance of getting them from activities they would otherwise stop doing? People are going to get to 34 soon enough anyway. Why not give them the option of actually having some variety once they get there?