I don't accept that God is all-powerful. He can't sin for one thing.
Sin means seperation from God. God cannot sin because God cannot be God and be someone else at the same time. This is the essence of monotheism. It is easier to believe in Gods endless possibilities than it is to believe that our own imaginations are capable of such thought.
As a monotheist, what I mean is that it is easier to believe that Gods imagination is literally limitless than it is to assume that my own human imagination is equally as limitless. I am not saying that humans are not creative. We are indeed creative, yet we are not infinitely so.