I see both Hermione and Harry coming back as very bloodthirsty. Compassion will have be burned out of both of them. But I feel it might be amusing to see Hermione not as the clever, cunning, 'smartest witch of her generation' but instead as a 'kill first, ask questions never' barbarian warrior. Less of a "take over the whole thing" and more of a "bring the whole thing crashing down around everyone" revenge.