I understand there are no real "supply lines" in this game, but even with foraging armies HAD to bring a certain amount of crap with them when they invaded places. A LOT of stuff came with them and it got increasingly harder and harder to replace all that crap around the further away you got from friendly territory. I think that if Lithuania is at war with Russia, they should NOT have the same amount of supply in eastern Siberia that they do in a province they border. Even taking in to account that this is a game and needs to be fun as well as somewhat accurate, I find this aspect neither fun nor accurate.
Actually no, the further into enemy territory, in general, the easier it was to supply "crap". Things like shot, gunpowder, and clothing all became a lot easier when your supply issues can be solved by "pillage the place". For instance, a lot of the French campaigns into the Low Countries received most of their gunpowder from Dutch merchants (i.e. the enemy). Artillery was about the only thing that you couldn't more easily supply in enemy territory than moving it from home. The truth is land transport was utter crap back then and just about nothing was easier to cart in by wagon than stealing it or buying it locally.
That even goes for manpower. A lot of times you'd have plenty of people who would either have ideological sympathies (e.g. French Huguenots often bolstered English forced) or a lot of people willing to take virtually their only shot at social advancement by signing on with the enemy. Further, a lot of you reinforcements (most I think) would be people recovering from wounds, illness, and general straggling.
Very, very little aside from pay (if you were paying the army in something other than plunder rights) and artillery were shipped to the front. Naval powers like the Dutch and English are the most common exceptions, and generally then only right along the coast.
As far as the OP's suggestion, this is one of the few non-horrid suggestions I've seen about forts. My problem is identical to that already stated: EUIV is almost a defenders paradise - defender gets terrain bonuses, defender gets siege attrition, defender gets higher supply caps/lower minimums, defender can scorch earth, defender gets omniscient information, defender can raise mercs right next door to shovel into battle, and defender has all the strategic advantages in the peace system. Attacker gets - initiative, some slight looting, and increases defender WE marginally by holding defender provinces (which is mostly not an issue before you've effectively won the war).
In realty wars in this era typically favored the offense for everything except sieging fortresses. Of course the average fortress in the era fell in under three months. Fielding offensive armies was typically cheaper. Battles were short so you couldn't even march armies from the province next door. Attrition was pretty much even handed - a giant stack of men caught diseases pretty much the same if they were bivouaced in enemy fields or their own fields. Pretty much every period commandered bought and applied the cult of the offense.
So yeah, I hesitate to tip the scales yet more pro-defender, but this isn't a non-starter. I stick think it will make life too difficult for the AI - hey hunter-killer follow my army through these lvl 3 forts while you rot in scorched earth attrition - but it is at least consistent with period tactics.
