Allow the barbarian king/archer queen to retreat from battle.
Have you ever been in a situation where your barb king/archer queen has finished its job but other troops are still working and you don't want it to get knocked out, because I have and had no choice but to hope it stays high on health.
If this was to be added there should be a "Retreat" button under each hero on the troop list and pressing it would make that specific hero flee to the nearest corner. One more thing, after its retreat it cannot be put back into battle if its in the same raid that it was told retreat, just so retreating isnt abused.