Currently an attacker has the huge advandage that he/she can destroy as much as possible from long-range without any risk.


If some long-range units (artillery, air-defense ...) would support reaction fire, the attacker would be automatically attacked if the unit enters the defenders range.


Option 1: 

Each auto-attack will reduce the number of turns of the defender.


Option 2: 

If the ammutation would be limited, it would increase the strategic options