There are some good suggestions below this quote, although I think it's great that the options are so simple already. There are only 3, you don't need to signal to players that each character name makes them act differently. Even if we added more, like 5 options, it's still easier for a player to understand than a list of names. So I think it's best to have the player choose their gameplay style (aggressiveness) and then have the game choose a personality which fits.
If we pick Defensive, then it can pick a random historical personality from that civilization who was considered a defensive leader.