Quote Originally Posted by Maloncanth
I don't think the AI cheats on the economy in the campaign map or economy on expert. I've played expert and hard never noticed any campaign map differences. Frankly, the strategic AI is idiotic no matter what difficulty you set it to. The only difficulty I find in Expert is that I'll lose 80% of my tactical battles, which basically means I'll press auto-resolve on most of them and still win. It's not really that much more difficulty, just a lot less fun.

EDIT: Of course, on expert, rebellions are more serious business than they usually are on hard, but on the other hand, it affects everyone, and the player tends to be smarter on loyalty management anyway.
As far as tactical AI is concerned, on Expert I would rate it as 'Slightly Moronic' as opposed to 'Almost Brain Dead' on Normal.