Memory
Storing AI data is often complex because the concepts being stored are not straightforward. In an individual level AI this will be less of a problem. We can store points and orientations and use numeric values to depict the "state" the AI is in. If the character is walking, the state equals one; if he's running, the state equals two; and so on. Now, how do we store more abstract information, such as the balance of power from the previous paragraph? And how about a path? How do we store a path so the character has a mini-map in memory and remembers how to go from A to B? Some of these data structures are trivial, and we will often end up with case-by-case solutions, especially when coding a master controller.