One of the most common arguments against the belief of God or religion is why are there so many innocent people suffering in the world? My answer for this is we have free choice, (as suggested in the story of Adam and Eve) I believe somewhere in our history we chose the devils way! In other words we made this world the way that it is.
I'm not anti-theist, if anything in terms of the God question, to me pantheism sounds interesting, but generally I'm just open-minded to the idea of God's existence or not. Regarding your point above, to me, that works perhaps a little bit, but what about the apparent cruelty in nature where man is not involved at all? I think the Creation story of Genesis to be allegory at best, Science shows quite clearly life on the planet is millions of years before we came on the scene, and it wasn't just peace and love then either, it was the tooth-and-claw of the jungle. Which to me, doesn't mean the universe is not sacred, but I do have a problem with the idea of a personality as God. It would have to be a pretty psychopathic personality if you ask me. Take the Biblical story of Job, for example. You have a good guy, God boasts to Satan how good he is, and Satan makes a wager with God to go and terrorize him with the most terrible afflictions, which God accepts! I really think (or hope, at least) these are really just made stories. Peace Brother!