[SurvivalistMerc]

Zen is absolutely right.

What I will add is that this ability is truly random and does not relate to the sort of commander he/she is or to how the commander acquired the experience.

For instance, I will often get "heroic battle prowess," which gives increased attack skill, on my magi. (Hand to hand combat where attack skill is useful isn't something my magi usually do.) Usually the ability is something you are able to at least marginally make use of, however. But not all of the abilities are created equal. I remember a time in the demo that an AI prophet who was a level 5 priest got quickness...he was smiting twice a turn!