if people don't know the tactics and how the boss works and don't lead the raid aka leave it to the tanks to do their job they don't deserve to take anything for themselves as they haven't done anything for it (and no putting the group together doesn't count, anyone can do that but as i have said not many people can lead)
if the only reason you make a raid is to reserve what your after with no regards to the other people helping to put that boss(es) then you are just selfish.
master loot was removed to try and remove some of the selfishness form the game