Personally, I think using an AI would ruin the idea of PvP which is basically what these sort of bordertowns are for. It's an easy solution, but I don't think it's the right one. What would probably be more in-line with the idea itself would be to change the town to neutral if the commanding player doesn't log back in within a certain amount of time (a couple weeks at most) It'd be easy to think up a reasoning too-Rebellion! Then the town would be controlled by a set AI and any player could go fight for control of the town and any bonuses it gave.
Which made me think of something- I was playing WotR in BFME today, and I thought that the bonuses players get for controlling territories would be great for this concept. For example:
Say a player controls a town in one of the neutral territories. That player could maybe hire a unique unit to supplement their armies with- not too powerful and the player could only control, say, 3 battalions, but it'd be a unique unit with unique abilities. Or, if that were to over-powered, the player could get a 5% boost to resource production at certain times of day. This way it'd provide unique PvP and a bonus to those who participate but people who don't could still play even with everyone else.
I'll even go to the trouble of providing an example of one of these towns:
Town name: Blanorn
Region: The Dirt Bowl
Blanorn is a medium-sized fortress ruled by a tyrant king. It's people live in poverty and fear but obey the king due to his power. He has gained complete dominance over two massive dragons that some say cannot be slain. The fort is set on a hill top by a small river with double walls manned by humans and dwarven mercenaries. It is very wealthy due to a nearby gold mine and thus it's forces are well-equipped and highly trained.
Begginning enemy forces:
250 human swordsmen, 100 Dwarven mercenaries, 150 human archers, 3 Drakes and 2 Dragons
The player that hold Blanorn receives 500 gold every 2 days and if they manage to remain in control of it for a week, receives a dragon to aid their cause.
^ That's an example, in my opinion, of what this could end up being like. Keep in mind that the rewards could be easily changed- I was just providing an example. The idea has me excited, as you can tell
There could easily be, say, a dozen to a score of these in existence with varying difficulty and rewards. The idea has tons of potential to be placed in an expansion. To me, right now, it sounds as if traveling to areas like that would only be for quests. No fun, right? What'd you guys think of my example?