I like the fact they are more aggressive, especially with other special units. I like a more challenging game.
But the diplomacy options seem a bit too situational for me. Although I can't really tell because they stop spawning after a while and the ones that do spawn are absorbed by other city states.
I was playing as Cyrus, waiting for me to get immortals, which took a while because of tech shuffle. And when I got them, I wanted to attack one of my neighbours and make use out of the barbs diplomacy, but they were all gone. Sad Face.
This is coming from me though, having only played one game with the mode on. Perhaps better luck next time.