When I played before BNW, I found that above Emperor level that the number of units created by the AI was nothing short of 'absurd'. It wasn't fun. Not for me anyway. It was always a matter of gearing up for 1 or 2 onslaughts with horde after horde headed my way. Now, although I've only played to 1500 AD with 4 different civs, I've not had to face any military opposition except for barbarians. In the last game, I expanded fast with the French and did face war with 2 nearby civs, but neither had any military units to throw at me. Given a choice between GK and BNW AI, I'd take the new AI any day. I haven't played even to a mid game yet, and I've read that wars definitely take place in the late game, but there should probably be some sort of aggression during the medieval era. Just PLEASE don't ever put it back the way it was before this last expansion! I'm excited to move up to immortal once I play thru a few of my emperor saves. And this is without a doubt the best game ever created.