Personally I hate the way loot is divided up in operations. There are a few reasons why I hate it so ill list them and explain.
1) There really isn't a social feel to the looting. What I mean by this is perhaps <<player X>> needs an item for 4pce and for <<player y>> the same item is just a slight upgrade because he already has his 4pce.<< PLayer y>> could pass on the item for<< player X>>, however this can't happen with the current loot system
2) Guilds are also prevented from gearing up people with specific roles first, perhaps tanks, healers.
3)IF people think that the loot systems stops ninja looters it really doesn't due the the fact loot restrictions are only on class items. People can still need on crafting materials and mounts, ect.
4) IT gives items to people that already have that item is it will now either be useless to them or it will go to their offspec where another person could have really used the item.
5) mainly though in general it just restricts the groups freedom with the loot which I think is stupid.