One of the general areas I have been looking to keep improving on the computer AI is its overall strategic overview. It's a tricky thing since even in multiplayer games, many tactics simply work well.
For example, "rushing" in on-line games is an age-old problem. My job is to take my online experience and translate it to having computer players that "feel" a lot like human beings (except minus the disconnects and a couple of specific game-related features such as your "diplomacy ability" affecting your relations positively).
Doing this has meant adding quite a bit of new text so that players understand what's going on. I've tried to make it more apparent when someone is being paid off to go to war with you than previously. But while I was at it, I thought I'd add more colorful text to existing areas as well.