Some recommendation's for more in depth soldier autocombat options:
When leaving it to the soldiers add 3 events with which you can decide to take. 1 neutral option, 1 strong option, 1 a weak option, which effects your army's strength. This can be dependent on the 4/3 nations biomes (since the wizzards is essentially the same as yours...), add generals which lead the enemy soldiers which swap out which options are each, then add the ability to observe the enemy army to understand the enemy generals personality which costs an extra action point.