Without the White Witch, Aslan is just a recluse lion. Without Moriarty, Sherlock is just a know-it-all in a weird hat. Without the Joker, Batman is just a rich dude with anger issues and too much time on his hands.
Our villains make our heroes. Without them, our heroes can’t shine. That’s why it’s important to give our villains scenes where they can wow us with their quirks and scare us with their ferocity.