I don't have quite the same problem as you (I'm often outnumbered on the strategy map), but I still agree. The boost to your chances is just too low to justify the cost, so I almost never use them. I'd much rather save the money so I can buy an extra Devasator next turn. I feel that Larian should both make them more useful and decrease the cost, possibly even to zero. Right now, I feel that Catherine and Edmund are so annoying relative to their usefulness that I'd like to just kick them off my ship.