I like what you did with the rules for the scenario. Hattin is a hard battle to duplicate on the table top, the movements of the armies was dictated by psychology and tactics that the player is unlikely to follow. However, having the Crusader forces slowly withering away (from turn to turn damage) does a lot to motivate the player to get to water. And it frees up the Saracen player to be the harasser, instead of forcing them to get stuck in to break divisions.
I ran Arsuf as a convention game several years ago, I may now have to give Hattin a try.