I'll tell you this from my experience with our aggressive rooster. We did everything bobbi-j is describing and it would work for a day or two, but if you slack AT ALL, he will take over again. Eat him. We ate our aggressive rooster and the hens are SO MUCH CALMER for it. He was so hyper vigilant that he'd get them riled up at every little noise. He'd attack the pop-door on the coop when we opened or closed it. He'd attack us THROUGH the nest boxes flying feet first when we gathered eggs and often plowing over a hen to do it. He picked his favorite girls and over breed them while neglecting others (we had 13 hens, his affections we're sure resulted in the death of one and then his beheading the next day) and he was so preoccupied trying to dominate us, that he wasn't being a flock protector. His favorite hens had ripped combs, rubbed up backs, and no feathers on their neck and heads. He was a bad bad rooster.
Think about this logically. Does the rooster need to protect the flock from you? No. Has anything you've done given him this impression? Not likely. Should the rooster be dominant above you? No. His constant attempts to dominate mean that he's not willing to accept his place, and any other aggressive animal that can't be retrained wouldn't be tolerated so why should he? As other's have said, a rooster isn't required to protect hens. Mine are doing just fine without theirs. They all ran for cover when the hawk came circling today and my outgoing curious Wyandotte gave chase to my recently adopted 10 month old kittens who are learning about chickens. Now that was funny!