This is a fantastic game, I'm having a blast playing it! What's the purpose of hiring another hero vs just building up your main hero's army? I can't figure out a way to combine both hero's together. I guess you can cover more ground with two hero's going in opposite directions.
There are two camps when it comes to hero hiring. Personally I feel there are very few times where it makes sense to split your army - so people like me just use number two hero to explore and ferry troops. But I know a lot of people disagree and use two heroes efficiently.
In v 1.1 you could use one hero to conquer land and another to conquer the seas :D