I know it can be frustrating at times when you are trying to pick up loot from a boss and someone is dropping their junk on top of all your new loot. I have a suggestion that might work but it would probably take a little time to make happen and test if this was something people liked.
Suggestion: Add a trash can space/area to players inventory. Disable the ability for players to drop items from their inventory in Non Hub areas.
This will solve two things.. 1. Looting without having to pick up other's junk. 2. Less clutter, better performance in zones.