I know the Baroness bows out gracefully in the end, but thats only because her attempts to to seduce the Captain failed because he is in love with Maria, and despite her driving Maria away she still comes back. She realised she couldn't stand in the way of true love. Plus the fact Maria has grown to love the children, and we all know the children wern't part of the Baroness 's plan. She wanted to send them to boarding school!
What a bitch!