Death of a Salesman: arguments supporting that Willy Loman is a bad man?

Well, I do disagree with your thesis. That being said, I'm very familiar with the play- studied it in University and acted in it in 2011- so I can help you out.

He cheats on his wife, buys the woman new stockings while Linda's home mending hers. His son finds out, Will never addresses this, instead he acts as if Biff's dopwnfall is baffling to him and lets the wedge between him and his son grow until they hate each other.

Throughout the flashbacks, we see that he had always favored Biff and Happy was always trying to get his attention and his approval. Yet, he never pays Happy much heed, always lets him feel like the lesser son and as a result, Happy grows up to be a womanizer and big talker- with no real success in his life and he's still that attention craving kid at the end of the play.

Willy kills himself. He leaves his family to deal with his financial problems and with the guilt that comes along with such a tragedy.

Willy is proud to a fault. He lies about his successes and refuses help when it offered to him (by his neighbour, can't remember the guys name, Bernard's father), he actualyy gets very angry when he offers him a job. Also, he's always belittling Bernard, even though he's just a kid, even as a successful adult, Willy treats him like that same geeky kid.

Anyway, there's some things to start you off. Like I said, I disagree and I think your arguement is a hard sell. All of the things Willy does are based on this ideal of the American Dream and, later, because of his deminishing mental state. But, as long as you can back it up in a thorough and thoughtful manner, you should be able to pull it off.

Best of luck with your paper and I hope this helped!