How about actually making the Antietam uncross-able except at historical points? :whistle:
Believe me it's not laziness and it wasn't ignored.. There is no way to make creeks or any other terrain completely impassable. All we can do is place movement penalties and there are limits on how high we can set it. Too high, and the troops will get stuck when they march on it.
This is a subject that has been beaten to death, but many have said that the creek
was passable and troops could have crossed it "without wetting their waist belts in any place". Others have said it wasn't passable. So in the game we had to come to a compromise. Troops can cross it but they are going to receive a hefty fatigue and movement penalty and are basically going to be sitting ducks to the enemy as they cross. There are also historic fords where troops can cross without penalty.
So again, we weighed all of the options and made the best decision based on historical accuracy and game play. It wasn't ignored.