The AI is still dumb unfortunately. However, now you'll see most civs make big stacks of Archers, making it harder to invade them, and the Sheaim will make big stacks of Pyre Zombies which are very scary. Unfortunately the AI can still be baited to have a stack of troops leave one city, whereupon you simply rush that poorly defended city and take it.
Another trick is to harass an outlier city of an enemy AI, the AI will feed a continuous supply of new archers to it, while you just pick them off, 1 by 1 and grow your forces to take their main cities.
Third, the AI still has a problem rush killing you, if you're in their territory, my Horse Archer spent several turns in Sheaim territory killing adepts, stealing workers, and pillaging.