I am really sure the empire needs a windsheild when fighting ewoks. They probably underestimate every enemy they fight so why go all out. Even if they had a windsheild it is not like they have good periphreals (spell check). The big ATATs had big weaknesses to. I am guessing they dont give a hoot because they rely on strong armour and sheilds. Ewoks are no threat to them in their minds. Have you seen a smart imperial. Do stormtroopers always hit their marks? NO. the empire is pure brute strength.