I expect that we’ll see a slight change in the AI behaviour eventually so that it’ll attack with multiple groups that are individually weaker than you, but stronger combined. This could result in bases sending out troops to help, if the AI feels like it would tip the scales.
Territory isn’t really a concept in the game, though .
Your first post talks about advancing time by an hour for every 3 rounds, not by minutes. The range implied by a battle taking minutes is already included in the current engagement radius and is actually rather generous in who can join the fight. There’s no gain in trying to complicate it further and would not be worth the effort involved.
In real life where battles could last for days, the actual fighting was much shorter. It could take a few hours, including capturing fleeing men, but most of the time was spent of camping and waiting for a good time for an attack (an extreme example, the battle of Tours lasted for 7 days Battle of Tours. Also these were large scale battles with thousands and ten-thousands of soldiers on each side.
In Battle Brothers we have only little skirmishes. These fights won’t be over in 80 seconds, but 10-15 minutes for a medium sized battle (12-12) with good armor on both sides sounds realistic. The largest battles would probably take 30 minutes at most, including hunting down routing units (i.e. finding that last archer).
Well, if you are ambushed in the forest, the enemy is probably very close, close enough for the combat to start in 1-2 turns. You could say the combat starts when your scouts notice something suspicious (shades moving between the trees) and then everyone prepares their weapons.
In other words, there’s no need to chance the game in this aspect. Reinforcements arrive if they are close by. Other enemy groups outside the battle couldn’t move much further even if the battle lasts very long. It’s working, it’s simple, leave it as it is.
Pretty much, yes, though interestingly enough, large battles like that are actually relatively less lethal than the kind of skirmishes found in Battle Brothers. There, having an army around means that you can prevent the enemy from pressing the advantage and annihilating a unit when they break or try to retreat, through the threat posed by others units (flanking, getting surrounded). This makes retreating more feasible, while in battles on the scale of Battle Brothers most of the troops would just die, since the enemy has no reason not to run them down when they can.