Well again, the issue i'm trying to address is that you can't manage your kingdom well. Here's my setup:
There's a castle guarding each of the two entry points to the whole south area there. But they're far apart. If one side gets attacked, even though I have 400 max tier troops in each castle, it will still lose to a large army (or they just walk by and siege something else), since I can't get over there to bolster the defense. Also, you only get alerted when enemies start a siege, so you can't really ever get into the castle before the battle starts unless you choose to lose a lot of troops to sneak in. You can't properly defend, really.