Making stable world is not hard. We just close defections, decrease sieges, make garrisons huge and give ai extra money to feed his garrison then its easy to make game stable. However it is not entertaining and it is not player-like ai playing. In every game you should see map is dynamic and take you in different direction. Of course one faction controlling all map is not something we also want to see. However we do not want to see stable world also. Currently AI is acting just like you same rules are applied everywhere. It makes no cheat. They pay their troops just like you they collect recruit from villages just like you, they suffer from raids, their economy get damaged after raids. There are lots of actions happening. There is starving effect on garrison sizes caused by raided villages also. All these mechanics make controlling snowball effect harder. It is also because we are currently at Early Access and development continues. Day by day game will be better and balanced.
Currently it is 5:00 am and I completely worked on this to fix this problem today and here is latest situation (screen is taken from 1095) :
You can see results in next patch I hope if it passes tests.
Just want to say thank you. Keep up the great work. People are posting because they love the game and want to see it succeed. I so happy we have devs like you on this issue.
Cheers