The broadest is the AI, which has become one entity rather than be split into a campaign-brain and a battle-brain. The effect is opposing battle generals acting according to an overarching campaign goal, which can be as subtle as not wasting effort on a strategically unimportant area, or as drastic as drawing players into dummy battles; distracting them from the real threat or forcing them to divide their attention. The battle AI itself has also been completely rewritten, and now reacts in a plan-based rather than state-based way, which prevents predicting that the computer will do A if attacked with B. Plus, these decisions adapt to suit the overall battle plan, which in turn is bossed by the overarching campaign plan. Even the generals have unique personalities that set them apart. The combined result is an AI that feels eerily human, and one that sparks battles with the element of surprise and unpredictability.
