How bad do bad guys have to be?

So here's the question. Lets say I'm starting a story with a bad guy, doing a bad thing. And I want the hero to stop him, in this case, by killing him (a variant on the throwaway victim used so often in horror flicks to set up the villain). But I don't want to tarnish the hero too much at the start. I know with a lot of exposition, I can create the characters demeanor, but exposition at the start of a tale leads to an editor tossing the manuscript onto the reject pile very quickly. So.....

Make the bad guy genuinely dislikeable. In Fact, make him detestable. What the hero does is a service to all mankind, getting rid of this kind of scum. Cheer for the hero, right from the first scene.

Is it overdone? Maybe. Every new writer thinks what he's doing is going to be different. "Me, cliche?. No, I'm writing this for the first time."

Anyway..... This is one of the possible openings I'm working on for Imperfect hope. Show the character of the character/protagonist early on, establish him as a good guy, but one who can be, has to be, brutal in brutal times. I'll let you know if it works.....

TTFN
Jim.