I think there was an earlier thread where there was some discussion on Captains, might be worth trying to seek that out.
For my part I find mine very useful, I'm using a Summoner and the Captain is a tank. I've built him with max armour and health, Possess him at the start of the game and then Leap him to the place where he can do most damage sometimes he does stuff, sometimes he doesn't. As with so many things in Frostgrave, it depends on your luck.