PS,
You brough up a very interesting point. I've thought about the idea of sin. The explanation of many religious beliefes including the one from the Watchtower is that humans lost their imperfection due to sin. You seem to think god messed with our DNA.
Why did god did not destroy Satan? I remember the answer from the Watchtower was that the angels were also watching, and what would they think if they did that. Since satan proposed that humans could reign themselves. (I think that how it went, it's been a while).
And I remember thinking to myself... Why wouldn't they have a problem with god cheating? Because god changing our DNA is cheating. I can just imagine satan going up to god and saying, "Hey, they don't need you". Then god turns around and says, "Oh yeah? Let me make a few changes here and there". And the angels are cool about it, but destroying satan, ho no, that would shatter their image of the great almighty wise powerful god.
What other changes did god had to do after the original sin? Let' see, he gave humans canine teeth yet he forgot to take out the wisdom teeth. He also forgot to take out the appendix, and so many other things. For being a very powerful being he sure has fucked up a lot of shit.
This is just a few things that for me, makes evolution have more sense than a story of a god.