Thing is, I think the entire point could have been driven home without the notion of midichlorians in both I and III. Shmi talks about the immaculate conception and not knowing what happened. Then Palpatine tells about manipulating the force to create life. Little force-sensing MITOCHONDRIA need not be present for the plot point to work just fine. Having the ability to sense the Force reliant on a microscopic life form totally destroys the mythic and religious aspects of the Force. It's like trying to say there is a specific part of our brain that allows us to know God (or not). Faith is removed completely by these midichlorians and it ultimately serves no purpose whatsoever, while actually disservicing the heart and soul of the entire saga. Might as well rename "the Force theme" as "the March of the Midichlorians."