Quod erat demonstrandum. You're restating the conclusion I already set forth in that he decided to create.
His motivation? Christ explained that in parables.
I'm not sure I agree with you here. Certainly, one can argue that Christ explained God's motivations for a creation already in existence. The question is, why does it exist at all.
People sometimes do things they don’t want to do, but I’m assuming God wasn’t under any duress when He created the universe. A true sovereign who is beyond anything that man can imagine would also be beyond any form of persuasion or duress, although there are incidents in the Bible where God changed His mind based on man’s entreaties. I think it’s also safe to say He didn’t need to create the universe, that is, if you define need as not being able to survive without it.
The Bible says God created man in His own image. I often create things for pleasure that I don’t need. My survival, for example, isn’t dependent on posting on Free Republic, but I enjoy doing so. If Free Republic vanished tomorrow, all of my posts (creations) would disappear. That would sadden me, but it wouldn’t threaten my existence.
I assume God does what He does because He enjoys it. Of course, none of us can really fully grasp a power or will so vast as His, but the angels rejoice when someone repents. Their survival doesn’t depend on that either, but it brings them joy. Does God experience joy?