I actually think a combination between personal loot and group loot would be really nice. All the junk items should be personal, as well some of the materials. high tier legendaries should be group loot. class related items should be on independent loot between the specific class - let's say 1 assassin item drops from boss X it should be lootable only by assassins but they have to roll for it.
Regards,
Shock! :)