Official campaign was just running trough even on hardest difficulty. Dragon part was the only place where I had to use tactics.
Artificial intelligence can never be perfect when it comes to providing difficulty. The more you play it, the better you start to know it and can anticipate it's next moves. Raising difficulty (monster stats, not ai tactics) is an option, but results in relying more and more on chance to instakill.
Adding more random factors, like environment effects and surroundings provide more interest to me at least.
From what I've read of Sawyer's replies, the difficulty on Motb looks good. I just hope that the combat pace is slower aswell, so there's at least chances for strategic thinking.