The AI shouldn't go bankrupt because it loses all its heroes in a battle against an enemy castle. Can it even have heroes that are purely for resource gathering?
In the previous version of the mod, enemy heroes moved in pairs on large maps. One with an army, and the other following closely behind. The second one collected resources, but not all of them, and also headed towards the nearest enemy castle.
Added after 34 seconds
Wouldn't it be possible to make the aggression level random? So that the blue faction attacks in the second week, while the green faction gathers an army and attacks in the fourth week?
Unfortunately, as far as I know, it's not possible to do that yet.