aerokes. You assume that god has the same ideas of perfection as we do. Why wouldn't he be able to have moods? Who decided that one mood is better than the other? Something that is beyond theoretical, or practical improvement, can still be changed. The change doesn't have to be for the better, or the worse. Just a change. My point is that there isn't necessarily one thing that is perfect, while everything else is wrong. Different people think of different traits as good. The way I see it, God should absolutely be able to change his book, without making it any less perfect.
As far as the entire mood thing goes, I look at it like this. Of all the flaws of our human selves, what causes most of them. Our emotion's, which controll our moods. on a simpler scale, what control's our emotions? the chemicals that make up our brains, and our body's, and how they interact with other things around them. If god is truly an omnipotent being, who does he have to interact with to change his mood, if he has one in the first place. The only people he would have to interact with is us, who he created to be where we are. So that would be talking to yourself.
You are also looking at everything to black and white. It isn't wrong to pick up a rock the decide to put it down, anymore then it is wrong to throw the rock instead of putting it down.
As i stated before, if god were to change his mind, it would mean that he either didn't like what he created in the first place, or his opinions change. How can something you know the outcome of, change your opinion once you see it happen? That would be like me writing a novel, and then halfway through the novel that 'I' wrote, start to sympathies with one of the characters, and change their situation. If the novel is how I intended it to be, and assuming god is perfect, it would be, then why would he change his mind. He would have the foresight to see himself now, and know what he wanted at this instant in time, therefor changing us in the original plan, to suit his liking for the future.