There's a very easy way out of that. Say God portrays himself as a powerful being to some forlorn proto-Jews. Out of fear, they agree to go along with it. Several thousand years of twisting his words later, God says "Enough". Then he sends a nice guy down as his son, to see if they'll buy it. Only a couple hundred years later, God says "Fuck this--they're not doing ANYTHING right!" and sends a tyrant to spread his word. Another thousand years later, and God's had it with his doings, and edits "take two". He then calls upon a polygamous creep from New York, just to see how it plays out. So far, not good.
Although this may say something about the longevity of benevolent societies, it is a completely reasonable progression. It'd be like he's already set up his great afterlife and all that, he's just working on communicating that to his followers. He's just sending around different editions of the same story, each time to grab a new audience.
He may be perfect and omniscient, but as he established free will (talk about a huge mistake), he needs to provide lots of options. Each doesn't necessarily invalidate any of the others, as each is targeted towards a different culture and mindset. I suppose this would make God the first politician?
Anyway, bankside put it better.