This idea is very interesting; I can imagine it as an opportunity to introduce smaller "civilians" who wouldn't have a chance in the main game or in a mod interacting with the main game.I can imagine other kingdoms on the Italian peninsula, or even peoples from the Nubian region, etc.This raises a question: is there a way to do this when creating a new random map, Selecting which type of vassal tribe will be present on this map will determine which units or bonuses will be available.  (Select this not at the player, but at the map creator)

Yes exactly. That's also what I was hinting to in my previous comment, and I was checking it and indeed : Melee eles champs : <Footprint replace=""> <Square width="4.5" depth="9.0"/> <Height>9.0</Height> </Footprint> Chariots : <Footprint replace=""> <Square width="11.0" depth="11.0"/> <Height>6.0</Height> </Footprint> Edit MB, actually Clearance wasn't used for what I though it was.

The next thing I will probably work on will be placement, making vassals spawn within random places around the map based on the number of players.  I can fix the resource thing after they are placed by placing some extra resources around them if they don't already exist. It's going to be harder to detect where important strategic areas are in each map though. One thing I really want to do, Is make sure the base AI in the game can also use them so they are compatible for single player. I'm not sure if the enemy AI will capture neutral/enemy buildings on their own, if so, then they are already compatible, however if they do not, the other option I'm thinking of is having the vassal town centres switch sides to their attackers at low life instead of being destroyed.   Edit: AI do seem to convert vassals and use them!

@Atrik I think the displacement (?) is just to big, maybe even bigger than elephant heroes. I frequently have chariots go around enemy settlements instead of straight through, because some shrub or something is blocking their path.

Probably just bad 'clearance' value for pathfinder, so trivial to fix. You could create an issue and attache a minimal replay on main with the bug happening that would very likely help someone to fix it.