The vex are pretty dumb, i mean, their high ego and smugness will get them killed. When you fight them they just take their time walking casually walking and shooting thinking theres nothing to stop them, it takes you shooting off their head to make them realize they arent smart enough to defeat you, and they finally start running at you and shooting like a wild west gunslinger. There head must be full of useless information slowing them down considering they fight better without it. And how the hell do they see and know where you are without there red eye sensor? Its literally useless.