I think Hans as a character was more supposed to be the guy you don't want your daughter to date rather than an "I want to kill them alllllll!!!!!!" mustache-twirling villain.
He's the flashy manipulative guy a young girl may first be attracted to before realizing that the less flashy guy with the heart of gold (Kristoff) may be the truly good guy.
That's pretty much how I felt about him. Hans is the guy your mom warns you about years before you start dating.