I thought of a fun and fluffy way to boost the Khorne Berzerkers' movement.
How about once per game they can move as if they are beasts (12", ignore difficult terrain, even fleet) but if by the end of that player turn they are not in close combat, they inflict 1 hit per model on their own unit at normal strength and distributed as shooting but ignores cover.
Call it Blood Haze. They get a little more bloodthirsty and impatient, but if they haven't satisfied their thirst shortly after they spill their comrades' blood. After all, any blood is still blood for Khorne