I would like this to be added, and it would also be good to hear the horn of the AI when they charge etc, will add to the game experience and provide awareness if for whatever reason you are looking back or flanking with cavalry, etc. currently, as there is no “strategic” map, there is no way to tell if the AI is doing something, which is kind of realistic, but sound would potentially tell you many things in the middle of a battle even if you could not make direct eye contact with the enemy, this could fill that gap as you cant really hear the sound of 500 people moving/talking/screaming in a valley in the game right now.
Having said that, it would be cool if either the closest soldier to the general/player uses the horn or if no close soldier is available, the general/player uses it, because otherwise, just hearing a horn without anyone using one would look weird...