Judith Warner has an insightfully honest look at why Hillary has trouble connecting on the stump:
Hillary's a real tear-stopper. She has a voice that is metallic and somewhat atonal. She has the sentence structure and cadences of a political science professor. I do not mean these things as insults; she is trying out, after all, for the job of president of the United States, not fairy godmother. Nor, for that matter, your best friend. Hillary's friends say she is warm and certainly very real. But she clearly isn't wired to project "realness' on the national stage. And frankly, for political figures, projection is what matters most.