The “spoils balls” that bosses and heroes drop should only be openable by explicitly clicking on them and having the character walk up to them and break them. They should not be breakable by any attack or skill damage.
This will greatly boost battle visibility by preventing large piles loot item names from covering the screen. This would be preferable to the only current workaround which is to manually increase the loot filter to show Epic+ items before or during a battle, followed by resetting the loot filter to the natural desired state when the battle is over.
This solution is even superior to the idea of having an additional hotkey which toggles between hiding all loot and showing loot based on the current loot filter, since that way requires manual loot management which distracts from the actual gameplay.