I have been playing raids for 8-hours on end trying to get an item, Sands and Oils of Time, only to be SLAPPED in the face to receive nothing out of my runs; even worse, the players that I've went with sat out the last minute and never participated YET THEY RECEIVED TWO SANDS OF TIME AND OIL OF TIME!!!
There needs to be a major improvement with your Need/Greed system and I know the best way to improve it for the better and actually return investment to your players and give just rewards to participants.