A villager after kill an unit should automatically attack another one

Well such a tech would need to be in castle age to not cause all the problems already discussed, but at this point the only thing villagers can beat are pikemen without blacksmith upgrades. And skirmishers ig but since said skirmishers automatically run away from melee units your villagers would get drawn away without any effort from your opponent 11. So it wouldn’t be a good idea.


Maybe you can just queue attack using shift, so they continue to fight

Simple. Just makes “villagers” auto-attack, not any other variants like farmers, hunters, miners, lumberjacks…
The game treats them as different units anyway.