Supply Line Simulation in Single Player - Suggestion
So this was initially posted way back when a video was released and in it, a lord gathered an army and raced right through enemy territory without consequences and besieged the enemy capital. After playing the game, this issue is certainly not fixed and it's still annoying and immersion breaking when it happens. There must be consequences travelling through enemy territory of some kind. Simply coding the lords to "only attack on the borders" is an ugly solution in my opinion. Here is my suggestion:
The Problem
A large army should not be able to march right through enemy territory without more adverse consequences. If so, then what is even the point of castles and fortified towns. Historically, you would have to besiege settlements to move further in land so you wouldn't be attacked from the rear and your supply lines wouldn't be harassed. Cause of this, most wars were fought on the borders and territory was periodically claimed gradually. I know that this an overly simplified look at military history and I'm sure some of you armchair historians can find obscure examples of armies moving through hostile land by foraging etc. Like Hannibal. Please don't bring it up here. I'm being very general and I'm trying to find a solution to the above mentioned problem in the game.
The aim of my suggestion is to build upon what is already in the game and improve upon it to "simulate" a supply line. The suggestion is meant to be something realistic that the devs could hopefully implement with some what little tweaking. As opposed to another system that might have them create actual units that bring supplies to and from armies in the game map. Or something that makes them change entirely how the game works at it's core. In an ideal world, we would have something like this. However, we have to work with what we have. I also want to make the game a little more challenging for the player and allow them to think more tactically about planning campaigns. But above all I want a system the allows wars to be mostly fought at the borders of the two opposing factions. A system that can practically eliminate armies sacking capitals deep in enemy territory as soon as a war starts.
The Solution
My suggested solution in a nutshell is to tweak the consumption of food in party inventories depending on your location and introduce an automatic resupply system.
Food Consumption and resupply
Firstly, the rate at which food is consumed should be greatly increased. Even with a full inventory of food, those supplies should last about 2-3 days till they are completely diminished. However, you also have a system where those food items can be automatically restocked if you are in friendly territory. This can be an option you can tick on or off. While ticked on your army will automatically resupply its food while moving within your own nation. The cost can be deducted gradually and the rate of resupply can also depend on the prosperity of the region. The devs can also consider making resupply free when you are in or around your own fief. This will allow you to operate within your own territory with relative ease. Giving you an upper hand against invaders. This is a war game so eventually you will have to attack your enemies and vice versa. The system still applies in that the rate of consumption remains the same but the rate of automatic resupply drops as you move further away from friendly settlements. Not saying it drops to zero once you cross from one faction to the other. It's about distance. Again this is aiming to simulate a supply line not actually create one. So disregard skirmishers harassing supply lines for now. So as you move further away from your last friendly town or village (maybe castle), your resupply rate starts to fall and your army will run out of food faster. You would need to take an enemy settlement or return back to your faction for the resupply rate to normalize.
Operating in Hostile Territory
You can still operate in hostile territory with this system. It just becomes more challenging. When you are fully in enemy territory and surrounded by hostile settlements your resupply rate will fall to zero. What takes over can be a foraging perk that can be added to one of the skills. Perhaps it could allow you to still get some resupply while in enemy territory. Of course a higher tier perk can increase the rate of resupply through foraging. However, the only certain way to stay supplied and prevent your army from starving is to raid villages. Since resupply is not automatic in enemy territory, you will have to physically raid around to get food in addition to having a foraging perk. And even then it would barley keep your army afloat due to an increased rate of consumption (consumption rate could increase when fully surrounded or it could also stay normal). Obviously this system discourages the payer and the A.I. from doing this for long stretches of time.
A.I. and Player Armies
So I don't know if the devs already have a system to "force" enemy armies to fight on their borders. However, I feel a system that organically does this is better than just having code script the AI behavior. For one it won't apply to the player and we would be free to rape and pillage unimpeded while the AI would be following the script. With this system the AI could be tweaked to understand the need for an automatic resupply. Just like when they are low on troops they go and recruit units or when they are low on food they go and buy some. The understanding of being resupplied in friendly territory and having none in hostile territory could be added onto their behavior. I don't believe it would be impossible to do so but I'm not an expert. Anyway, this understanding would make the AI (hopefully) fight generally around their borders. And invasions and sieges would be against settlements closest to friendly ones.
Adverse Effects and Other Factors
The first and most obvious effect of not being supplied is morale. The morale of the army can be affected slightly by the rate of resupply. So the negative morale effect increases the further you get from friendly territory. While isolated in enemy territory, the base morale hit would be substantial unless you are raiding and pillaging. Other factors that can affect the rate of resupply is the weather. A feature we haven't really heard about in a while. During winter the rate of resupply could be greatly reduced. This would make campaigning in winter quite hard. On the flip side, during the spring and summer the resupply rate could be at it's peak. It would make those periods ideal for waging war and invading enemy territory. Another factor is moving through Neutral territory with your army. This could just change the cost of resupply. Moving through neutral factions to get to the enemy would just increase the cost of your resupply unless the faction is your ally. In which case the prices are normal. A host of little additions could be added to make the system more robust. For example, your relationship with notables or settlements could affect your resupply cost and rate in a particular area. The same goes for your relationship with other clans and lords. I strongly believe your resupply cost should be lowest or zero and rate should be at it's peak in your own fief, regardless of notables and relationships. However, this can be tweaked around a bit.
Tweaks
This system is by no means a perfect solution and would have to be tweaked and tested extensively before it functions as intended. The rate of consumption and resupply would have to be balanced to make the system challenging but not tedious or annoying. There would have to be a happy medium. The price of consumables would also have to be tweaked. As will the price of automatic resupply. You could also reduce the price for resupply if the character has a foraging perk. The Supply Line Simulation is just meant to build upon what is already there and to add an extra layer to the grand strategy element of the game. It would make factions fight on their borders more often and also make sure that they gradually invade territory, taking one settlement at a time in a manner that makes sense. Not run straight at the enemy capital. Of course it could be more complicated than this but the whole idea was to make a system simple enough for the devs to hopefully take notice of and implement. I feel this could work very well.
I tried to keep my suggestion relatively short and concise to allow for discussion. I also wanted to avoid a wall of text as much as possible. Please let me know what you think. Am I making sense or am I talking out of my ass?
Great additional suggestion:
The problem in warband was that you could buy one "piece" of bread which would feed dozens of men for days, which is long enough for you to go round the whole of calradia half a dozen times, which in turn meant that you couldn't prevent an enemy from penetrating your borders by cutting their food supply. But more rapid consumption would just make the game a tedious stop-start of constant buying. I think therefore that food should be acquired by adopting a specific "stance" which would automatically fill your food as you travelled based on your surroundings. Maybe there could be little bars above towns which would show how much available food you could buy and how much you could take by force.
These stance would be like this:
Idle. Don't take any food, rely on own baggage.
Buy. You automatically buy enough food for your army from surrounding villages, perhaps with a slider allowing you to either buy up all the food in the area (and deny the enemy), or buy a less than ideal amount in order to save money.
Raid. Your men occasionally detach from your army to go and take food from undefended hinterlands between villages, with some consequences like wounded men returning and an overall slower movement speed.
Scorched Earth. Your men take what they can and destroy the rest, making it difficult for an enemy to follow you without suffering.
Supply Train. Trains of food are sent to you periodically from nearby settlements meaning you don't have to rely on any of the above. These would be actual entities in the game which could be attacked.
I definitely think that the result of going into an area of low supply should be almost immediate, otherwise the effect on actual playstyles would be minimal