Hey OP this is a great idea but I think people on forums and reddit in general vastly overestimate the number of people who have completed the raid. You generally get matched in game with people close to your level / location. If you check the trophies on PS4 only 15.2% have completed Normal mode with only 6.6% completing hard. That means the vast majority have never experienced the best part of the game and I would say are much less likely to keep playing. I hope they can think of something be that MM or whatever to get that number up as I would say most people who do the raid are guaranteed to get the DLC and stay with the game. Best of luck for helping everyone! I'll be on in 13 hours or so helping a 27 friend do a run with some other friends if anyone is on and free then.