I disagree to be honest. If the result of battles is this easy to determine then it might as well be autoresolved.
I did say "guess" and "rough guide". There would still be the existing RNG involved in the battles between the troops, and unless balancing was done really obsessively, it would only ever be a
rough guide, as opposed to a hard rule.
The thing is, it wouldn't just be tier of troops and quantity of troops you'd need to take into account, in my ideal world. You would also have to consider unit counters (not really a thing right now), global morale (not really a thing right now), individual morale (with its own RNG factor), formations, flanking/encircling, and terrain, plus your own impact in combat.
My favourite battle system is Rome 2 Total War. The expensive units in that game are extremely good, but only when supported by cheap light units. The cheapest spearmen can out-manouevre and javelin elite cataphracts to death, and the cheapest slingers can beat the most expensive infantry. You end up with about 20-30% of the army being heavy infantry, with maybe just one unit of elite infantry.
That seems to be the same as what I proposed in my post, a soft-counter system, where lower-tier units can defeat higher-tier units if they counter them.
Unless... is the difference that you're saying that the cheapest spearmen should be better at countering elite cataphracts than the most expensive spearmen? Because in that case (not having played TW Rome 2 myself), I don't see what role the expensive spearmanii would even have.
Why is it so important that cheaper units need to be kept just as good in a fight as their more expensive counterparts? The advantage of cheap units
is that they're cheap, and so you can mass them.
The way I see it, with upgraded units being straight up better but a soft counter system, the T3 Pikeman's role is to counter T3/T4 cav, and go even in a fight with T5 cav.
But against every other T4 unit, the T3 Pikeman will lose.
So a T5 Pikeman does his job better in every way, but is more expensive. The money you spend on upgrading to a T5 Pikeman could be spent instead on upgrading two recruits to T4 Pikeman and T4 Heavy Infantry, to provide protection from arrows which you wouldn't get if you upgraded to T5.
That way everything has its role in a limited army budget.
Low-tier cheap units provide numbers.
Mid-tier units provide versatility, to protect against being countered and increase the opportunity for countering enemy army compositions.
High-tier units are the best fighters, but by upgrading to them, you lose funds for army diversity and run the risk of being countered.
The problem is that battles in bannerlord are mostly just doing as much damage as quickly as possible. Flanking does almost nothing and wastes valuable grinding time, rear charges just get your own cavalry killed, the only tactic that reliably works is to mass archers and kite the enemy in front of them.
Agreed. Armor weakness, combat AI being superhuman in some instances and moronic in others (e.g. infantry whipping around at lightspeed to use their dagger to perfectly stab the charging cav that just flanked them, while said cav are unable to hit anything with their lances), and morale mechanics (basically not existing above T3 and having no global element during battle) seem to be the main issues.