At the start of the battle, you have complete control of your troops. You can order one flank to stop on a hill, send your cavalry in a wide flanking manoeuvre etc. You have RTS style "omniscient god"like control of your units. But once you order a unit of troops into battle, you have to accept that you are likely to lose control of them, at least for a good portion of the battle.
- Once a unit of infantry engages in melee with another unit of infantry, they are likely stuck there fighting, turn-after-turn until one unit breaks.
- If the opposing unit gets pushed-back, your own troops might push forward to stay engaged, or they might not. You don't get to decide.
- If an enemy turns and flees, your unit might give chase without your order. (Some unit types are more likely to do so than others).
- If you charge infantry towards skirmishers or cavalry, they might dance away before your units can catch them.
Not only does it feel authentic, but it adds randomness to the battle in an interesting way. Normally I expect combat randomness to be "I might do alot of damage, or very little damage". But this is a much more interesting type of randomness. Will my victorious troops push forward, or hold-the-line? That second type of randomness is much more interesting, strategically. Rather than "how much damage did I do?". It makes every battle feel unique and interesting.

