Well sun tzu had understanding of physcology and if you put a man on a hill he may not willingly come down but if you put him in front they will be more willing to go forward for a charge. And when all is failing you can withdraw them to the high ground.
An example from MTW I can give is look at how hard it is to bring cavalry around on the rear when you have to run them up a hill first and the charge. Usually by the time they swing around the battle is already won in the front thus allowing them to turn and fight there new threat.
1 big problem I see though is it could keep them blind to a major ambush where an army would hold off engagement and the sign for the mainline to charge would be seeing this unit pop on top of the hill and cause them to be charged from both sides. And the only way to counter this would be to have good scouts and getting a report from them early enough and charge before they can complete there maneuver(attack while there forces are split and have less flexibilty) this way you defeat there army and any smart general would stop his maneuver and go back home. Of course scouts can be killed and it would be easy to forget that they have not reported back yet.
Bookmarks