Hi, outnfree:
First, I do not take the book of Genesis literally. It was not intended to be. So when I refer to a scripture there, it is for the underlying analogical value. That is why I say Gen.3:22 is a "clue".
In the creation story, it says that man was made in God's image. Yet, evidently we cannot be in God's image without understanding good and evil. That is why God--in the story--would say: "Man has become like us, knowing good and evil."
I don't know your religious leanings, but if you are Christian, think about this: IN THE STORY AS IT GOES (pause for this to register). . . If Adam and Eve had never sinned, and had eaten of the tree of Life, the implication is that we would all be here forever, overpopulating the earth, never dying, never going to heaven or anywhere else, but running around blithfully naked in a lush expanding garden. To carry the scenario further, once the earth would reach a full population, would sex and marriage would no doubt desist? And people might eventually wonder what those annoying physical differences were all about, etc., etc., etc.
My belief until something better comes along is that this is the life of the knowledge of good and evil. It was designed to be. This earth is essentially away from God's presence, and it is through death that we will be born again into a spiritual life. That is what Christ was trying to explain to Nicodemus imo. In the edenic story, the only way to die was to sin. The only way to get born into spirit is to die.
Opinion: In order to experience good, to understand it, to have joy, we have to have experienced the opposite.
This is my philosophical viewpoint, not carved in stone, and I'm sure others here on both sides of the skeptic/believer debates will consider my viewpoint to be folly. Fwiw.