Are you saying not giving away something you get is the same as taking something away from someone else? Because thats exactly the difference between keeping an item you got from personal loot and needing on an item you don't need.
Also, there is no need to wait at all. This shit has already been tried twice: Whenever Dragon Soul came out and whenever they reverted personal loot in dungeons in WoD. Both got massive backlash and in the WoD case, was quickly reverted to how it was. Group loot in pugs is unnecessary drama.