Well, to explain, I would say from premise and 3 and 4, draws the 5th premise that "f God created everything, then everything should be good."
To expand further, you suggested: "If I were an intelligent being, does that mean I could never do a dumb thing? I think a good being could create something that was evil and it would not impact the nature of the being to do so. "
Well, you would actually never do a dumb thing if you were all wise, and all knowledgeable, or also known as omniscient, which means you have infinite knowledge, one that is immeasurable, nor incomprehensible by a mortal with a finite mind.
I think a good being could create something that was evil and it would not impact the nature of the being to do so.
Well, it's hard to say, based on a logician's view point, an infinite good being that can create evil is a problem, because it would be a contradiction. It's like saying an immovable rock will meet an unstoppable force, or saying that you are taller and shorter than me. A God, if it existed, would be limited to the logic realm, because if it did something illogical, then God can make itself not exist.
So to summarize quickly, the point is that God cannot do something that is a violation of His own existence and nature, which is not really a limitation by God, but a necessity for God to exist.
I have heard many atheists trying to get God to be illogical, but their own paradoxes that they come up with are self-refuting and invalid in the logical sense.
A contradiction (illogical aspect really) is why the famous quote falls itself flat on the face, and it goes like this, "Can God make a rock so big He can't pick it up?"
So the 5th premise is strong, and now the argument that will make or break the whole argument is free will.
If free will is inherently evil, then it means God can do contradictions, as I explained above, which means a chain of illogical thoughts, that will lead to nowhere, but a dead end, and it is like trying to assume or make God illogical.
If free will is inherently good, then it means God is not committing a contradiction by allowing humans free will, and logical aspect of the state of God is in place.
Then theists can argue using some form of Alvin Plantinga's case where he says "It is possible that God, even being omnipotent, could not create a world with free creatures who never choose evil. Furthermore, it is possible that God, even being omnibenevolent, would desire to create a world which contains evil if moral goodness requires free moral creatures."
And, since you brought it up, I'm not an atheist, I'm somewhere between a hard and a soft agnostic. I endorse neither position of atheist or theists, but just interested in the logical arguments that are brought up by both parties, that go somewhere along the line to say God does exist, or God does not exist.