Ramayana: Why is Ravana being treated as a villian?

Rama gave Ravana enough opportunities to return sita and get his pardon. Ravana was so proud that he felt Rama could never defeat him.Rama accepted the challenge and the result wa destruction of Ravana. But Ravana is ot treated as villain. He was a great scholar. political administrator and a warrior of super cl. So Rama tells his brother Lakshmana to take these lessons fro Ravan in his death bed.Accordingly Ravan also magnanimously teaches lakshmana.