I'd prefer to have "evil" as a word removed from language as an archaic symbolic reference to bad things that some people think that other other people do under the influence of malevolent supernatural beings. Redefining evil as something else is still clinging to the religious connotations like a baby to their nappy - for a reason: it's because it elevates my/our value systems from a mere subjective one to that a presumed spiritual realm, and therefore objective of sorts.
But the hard truth is that value systems are objectively subjective, and people can be confused, ignorant, frustrated, angry, insane, devoid of empathy, people we don't like, or our enemies - but not evil. It's time to let that term into the dustbin of history.
So, you need the supernatural connotations in order to explain that Hitler was bad? Feel free, but to me the problem is the anti-intellectualism of it. Because "evil" is a self-sufficient explanation, which doesn't explain any of the real reasons for the rise of Nazism and cloaks the fact that ethnic cleansing and genocide are very much human behaviors, which history has sadly proven again and again. We're not getting to grips with it by calling it "evil" (or "Evil!!" even), which is mere name-calling, essentially. Name-calling of others that is.
But the hard truth is that value systems are objectively subjective, and people can be confused, ignorant, frustrated, angry, insane, devoid of empathy, people we don't like, or our enemies - but not evil. It's time to let that term into the dustbin of history.