His hook box is actually broken. I don't what the shape of the hook is especially when the part of the hook that is flat is catching people outside of its animation. Make it less forgiving. I'm able to land hooks in places and in ways I'm not supposed to.
Remove the slow from his E. Support players can just walk up to you, flay you towards them and you're slowed. This allows them to hit their hooks easier since you can't run anywhere. It's also adds a bit of excessiveness in certain situations. It can already displace you either towards an intended target or away from a target.