Why would God create? Doesnt any change in the Omnistatus-quo imply imperfection, a lack, mere room for change? Is boredom or loneliness or even the desire to acquire the emotion of sharing, a flaw in God? The perfect flaw?
Another way to look at it is "what could God create?" Simply (or not. See Emprophs contemplation) Not God. Other than God. And other, though made of Godness, is NotGod anymore. Your nail clippings are not you. We are not Him, nor will we be again.
Perhaps, at least from what we see on this earth, Nature was not enough. It reflected Him, was perfect, but didn't "know" it, couldn't "know" Him. It still WAS Him. So from it He pulled something that could see Him, see It and see Itself. And as a self, could prefer itself. It was a necessary risk. It was the best way for God to meet His goal.
I think in a sense, we are God's vacation from being God. We are the way for Him to get out of Himself, to know Himself from a different perspective (the Tao SoulInvictus mentioned). Each Soul, each life, is a carnival ride He can get on. Knowing how it ends doesn't diminish the experience. Perhaps when all's said and done (question 13? ) our knowledge of each other will be similar and we truely learn to see the world through one anothers eyes, and live through those eyes as God may today...