What I notice in Genesis 8 is that in verse 21, the LORD declares that He will never again do what He had just done, because the intent of our hearts is evil from our youth. This reminds me of His stated rationale for the flood in Genesis 6:5, which was that human hearts were continually evil. In other words, punishment for evil, while clearly necessary at times as a judgment, does not solve the problem of evil except through annhiliation. How can the LORD solve the problem of evil people without just totally destroying them? The story of redemption runs throughout the Bible.