i noticed before that low amount of troops do high damage, more than the should be, so finishing off was much better than damaging more
usually its a damage output which you can use to kill or damage units, for example 7 treants do like 800 dmg, or 4 do 400 dmg, you can calculate that you could kill the remaining 40 orks or rather kill the 60, it seems logical for most players to let alive the 40 and kill more from other troop
usually it was better to go for sure and kill the ones already damaged, have more troops, more action points, than do max damage and receive one more round, hope this fix it
this will be better for elves, as they got more hp, less dmg, so bit longer fights, also this improves the tactic of killing ranged units and let melee hit you, basically tanking opponents over
ai dont really focuses on hitting the backline, maybe just the wardogs, staying out of range benefits the players, its more realistic this way
gives bonus for landing first hits and peeling, and punishes less for missing last hits
there are some countering phases when you can let 5-10 soldiers alive, focus others, receive damage and let them die from the counterattack