The Case for Pettigrew & the Case Against Snape

This isn't going to be a full-scale essay - no time for it, what with teaching starting soon and my perposterice challenge fic to write (how dare you insinuate that I can't write a fic about words and chickens that will make you laugh and make you cry? Bitten off more than I can chew? Moi?) - but after reading the latest episode of KazVL's Falling Further In, follwed by an evening spent watching the Prisoner of Azkaban DVD, something struck me rather forcibly, and I was wondering if any of the wise readers of this journal had any thoughts on the matter.

The thing is this - the frankly very average looking Severus Snape killed Albus Dumbledore by his own deliberate act. In cold blood and in front of witnesses. He then ran off.

The frankly very average looking Peter Pettigrew contributed to the deaths of Lily and James Potter under circumstances that have never been fully understood but which we are led to believe involved considerable coercion from Voldemort. He did not kill them personally. Then he ran off.

Now there are plenty of people in the fandom prepared to swear through a brick wall that Snape is as innocent as the day is long, and good-looking to boot. Not just a few oddballs, but really a lot of people. 

So why is it that so few members of the fandom are prepared to stick up for Pettigrew's morals or looks, even before he did That Awful Thing? Writers regularly endow Snape with looks and sex appeal that canon has given him no right to expect - why is it that the best role that Pettigrew can hope for is comic relief? Why do we never get TorturedSexGod!Pettigrew?

I have no answers to these questions, but I'd love to hear yours.