God hardens the heart of the Pharaoh because it makes for better story telling if against all reason he continues to resist keeping his own promises, and god can keep mucking around with the laws of nature.
In such a scenario, I don't think god comes out looking particularly rosy.
The other thing that struck me is just how weak and pathetic the Israelites turn out to be once they follow Moses and Aaron out of Egypt. They are weak-willed to say the least, and from what I know of the story to come, lacking in self-control, loyalty, faith, and a whole constellation of other positive traits. These hardly seem like the chosen people. These hardly seem like traits that should be emulated. If they are really that pathetic, why should I conclude that they are god's chosen people? To me, chosen, should imply "better" in some tangible sense... oh, kinda like evolution would do.
But hey, maybe that's just me and my materialist sensibilities talking.