"Then, I suggest you let him do his job," he said. "We'll think of something. You just can't sweep in and take over, though." He doubted that anything Severus would do would discourage the Dark Arts.
"You do realise that you are the best advert for the Dark Arts, right? Powerful, knowledgeable, Death Eater turned Hero and now Headmaster." If Severus were a little less reclusive, they'd be beating down his door. "You won't exactly discourage them."