I don’t remember which stream it was or which person said it, but one of the devs said there would be variance between the Three Kingdoms but that they didn’t want to make it so you had to choose one based on your style of play.
The example they used was that giving the Northmen’s Alliance like a 10% fighting advantage would kinda make it so if you were a militaristic player that the only logical choice for a kingdom was the Northmen’s Alliance, and they didn’t want that to happen.