I've noticed on a number of occasions that when I try to raise an AI territory, the AI does nothing about it. 

In fact, it has the ability to as seen in the following screenshot they have a Mongol horde against a single scout and will just stand around doing nothing for many turns. 

auto-save 8208.ctr

I hope this isnt a result of the new deplomacy mechanics because its not appropriate for an AI to be completely passive like this.