Yeah I'm gonna first post this that's how much I hate sentry. Sorry to revive an old thread.
People hate him because he's a poorly created character in a comic book universe that doesn't need another one (other characters in the marvel universe that have shoddy origins have been accepted for legitimate reasons). His only redeeming quality is that he was extremely conflicted, but the dynamics of this character makes the marvel universe seem cheap regardless of this one redeeming quality (which did make for some interesting story). That being said I think that his strength and abilities need a cap in order for him to be more acceptable. There are things about the sentry that were refreshing but honestly they could've used already established characters to do those things... the whole super soldier serum thing just made me laugh the first time I read it. The only things I feel he resembles superman in is the tights, cape, and clean cut look... other than that they are really two different characters. At first glance it is something that just clicks though so it's no surprise that people make that initial assumption. After all superman is the first superhero of the modern age and he coined the tights and cape look that the sentry rocks it isn't a mere coincidence that the sentry was created like that. Maybe it was a jab back at DC for having taken shazam away from marvel. He's a generic character that needs to stay dead. And I hope more characters join him.