10 Additions We'd Like To See In Total War: Three Kingdoms
5. Make Defending A Vassal More Positive
A major complaint since the game's release has been how vassalage works. I mean, it's been on this list twice already, so what's a third time, right? One of the biggest complaints had been that Yuan Shao had a habit of vassalizaing everyone on the map around you causing massive extended wars. One of the first patches fixed this problem a bit, but it didn't fix all the underlying issues with vassals.
If someone declares war on your vassal you have two options: Defend them or abandon them. If you defend them, then you declare war on their attacker, but if you abandon them they become an independent faction again. As one can imagine, abandoning someone who is literally paying you for protection raises your treachery attribute. The problem here is that defending the vassal often raises your treachery attribute, as well, because you might have a treaty with the faction who attacked your vassal. But the AI forces don't suffer from such an issue.
If you attack the vassal of someone you have a treaty with, that's considered treachery because you're also declaring war on the vassal's master. So the game knows that the master is connected to its vassal. The easiest fix would be to take away the treachery penalty for defending a vassal – the game should recognize that the instigator of the war broke the treaty, not you.