Well considering the Armour itself which is probably adding a bit to the body the head size could still be justified. Like hes got to have some mobility with his head so he can look around. otherwise its just too dam clunky. That's just my opinion though.
Heh,well I wanted to make the Ares look like they can eat bullets and still stand on their feet... It's actually their armor that's making them look disproportional-it's very thick and broad,unlike the Enai's.