Maybe on higher difficulties AI should be more risky with their units, because they can have them many more thanks to bonuses.I completely disagree ... I wonder if you even played back then .. they would take damage YES, but they'd also RETREAT if very damaged - which means that a healthy unit would replace it's damaged counterpart - just to continue the process! Sometimes a city fell in just a few turns, if one had failed to build walls. One was never safe!