BlueCardinal said:

I don't know, it kind of makes sense to not have any Imperial ground troops in this battle. The Empire has these huge walkers that are almost impossible to take down, so just let them stomp their way in and take out the shield generator so that Vader & Co. can land. Why risking losing men at this phase of the battle?

Because it's Vader (and by extension, Palpatine). Since when did these guys ever display a conscience, or military cunning? Especially about an unlimited renewable resource like Easy-Bake Stormtroopers?