The reworked military alliance system in Warhammer 3 is awesome and I love the outpost system. Being able to recruit units from other factions is a really nice addition.
However, I have been noticing that AI factions will always try to build an outpost on their military allies' settlements whenever they can. The issue with this is that since there is only one outpost slot per compatible settlement, that slot is usually always occupied by an AI ally of the faction you are allied with. And more often than not, those slots are occupied by allies that are of the same race as the faction you are allied with.
For example, imagine you are playing as The Ice Court and you sign a military alliance with Reikland. Typically, as a player, you wouldn't normally make military alliances with the AI until a bit later in the campaign, so as not to be drawn into unwanted wars. So, by the time you ally with Reikland, they are probably already allied with most of the imperial provinces (if they haven't been vanquished by the ogres, that is).
So, when you go to build an outpost in Altdorf or any other compatible settlement, you will find out that, for example, Stirland has already built their own outpost there, locking you out.
This is when you realize, why the heck would Stirland want to build an outpost in a settlement occupied by someone of their same race? To be able to recruit different coloured empire spearmen?
It makes absolutely no sense, in my opinion. It has happened to me many times that when I become military allies with another faction, they usually have all of their outpost slots occupied by factions of their same race, which is dumb because those factions cannot take advantage of those outposts, because their roster is the same.
My suggestion is to tweak the AI to limit or outright remove their ability to build outposts on their allies' settlements if they are of the same race as them. This would also allow for more varied armies across the campaign, not just the player's.