Challenger Class Equalizers:
Every AI starts with a worker, in addition to their contender units. Now I know what you're thinking... 6 free workers to steal! Before you get too excited, you might want to re-read the bit about AIs being able to defend themselves, and consider: Would the mapmaker really be silly enough to make the challenger save easier than the contender save? Of course, you might consider that there are possible trading advantages to having a more powerful AI anyway... that's up to you and your playing style.