having war caravans is something will have no impact on the game as of now since most armies simply either disperse or get captured before they begin to starve. however, as the game develops, it seems like the developers' solution for "settlement swapping" (settlements constantly switching hands from one faction to the other) is to slow down sieges (they slowed making siege camp by 33% a few patches ago). and as they continue tweaking food consumption and the speed of mounted troops then food can become an issue. you want to know why a 1000+ man army is raiding a small village instead of actually sieging? that army probably is low on food. now they could make raiding better, but my point stands; there need to be a form of resupplying. war caravans can sell food (for a high price, of course) to armies, not only of their own faction, but to any neutral one as well. players can form these war caravans as well, though they should cost more to form them. also, having war caravans filled to the brim will food and good can make raiding these caravans actually worth it. most of the time raiding caravans isn't really worth it as the loot is worth maybe between 1000-5000 Denars, but raiding war caravan should give you a stupid amount of food as well as screw an entire army up, making it more worth it.