I've always disliked simplistic interpretations of Severus's character - one way or the other - because, if anything is true about him, he is complicated from the word go, and the more JKR told us about him the more complicated he got. Your comparison of him to the classic traits of a Byronic hero is just wonderful. Almost against her will, JKR created a genuine anti-hero. His resemblance to Heathcliff is astounding for someone who claims never to have read Wuthering Heights, with perhaps one crucial difference: there is no evidence that Charlotte Bronte despised her own creation, whereas Rowling most certainly does (or did - I think we fans are having something of an influence on her. She has been much more equivocal in her pronouncements about him lately). She patterned him after a teacher she hated in school, whom she thought bullied her and made her school life a misery, and Snape's character was meant in some ways as an act of revenge. But then she gave him that tragic backstory, and undid, for a lot of us, the ability to see him in a purely jaundiced light.
As much vitriol as gets thrown at Severus, it always astonishes me that the Malfoys are never painted as even more horrible, even though, objectively, they are. You never hear anyone spouting at length about what an evil character Lucius Malfoy is, do you? The Malfoys have power, money, beauty, and sit at the pinnacle of Wizarding society. Yet that power and privilege was used for evil; he was taught to despise those not from his own class and blood status, he joined up with a wizarding supremacist organization in his youth where he participated in atrocities, lied and bought his way out of the consequences of that when it went pear-shaped (and he could do this because of his standing in society), continued with his misguided beliefs even after Riddle's first downfall in spite of public professions to the contrary, abused and maltreated his house elf, attempted to use a *child* to continue Voldemort's work at the school (there's no evidence that he knew what he'd given Ginny was a horcrux, but he understood that it would possess her and cause her to open the Chamber of Secrets), knowing that children would die and that the child of a pureblood family whose political opinions were contrary to his own would be blamed for it. When Voldemort came back, he was among the first to return to his side, leading his wife and son right into the cesspool with him, whereas Severus returned only to work for Voldemort's defeat. When Voldemort turns on him and his family in the wake of the fiasco at the Department of Mysteries, we're supposed to feel a bit sorry for them.
Carried Away, part 1 ::g::
As much vitriol as gets thrown at Severus, it always astonishes me that the Malfoys are never painted as even more horrible, even though, objectively, they are. You never hear anyone spouting at length about what an evil character Lucius Malfoy is, do you? The Malfoys have power, money, beauty, and sit at the pinnacle of Wizarding society. Yet that power and privilege was used for evil; he was taught to despise those not from his own class and blood status, he joined up with a wizarding supremacist organization in his youth where he participated in atrocities, lied and bought his way out of the consequences of that when it went pear-shaped (and he could do this because of his standing in society), continued with his misguided beliefs even after Riddle's first downfall in spite of public professions to the contrary, abused and maltreated his house elf, attempted to use a *child* to continue Voldemort's work at the school (there's no evidence that he knew what he'd given Ginny was a horcrux, but he understood that it would possess her and cause her to open the Chamber of Secrets), knowing that children would die and that the child of a pureblood family whose political opinions were contrary to his own would be blamed for it. When Voldemort came back, he was among the first to return to his side, leading his wife and son right into the cesspool with him, whereas Severus returned only to work for Voldemort's defeat. When Voldemort turns on him and his family in the wake of the fiasco at the Department of Mysteries, we're supposed to feel a bit sorry for them.