I don't think she is as "dumb" some are trying to paint her. Her performance during the convention, and the accolades she received for it, from both sides, disprove that claim. I think we will need to see how the debate goes before reaching any kind of conclusion about her communication abilities.
Her performance at the convention was just that- a performance (something all politicians do). Reading a teleprompter and answering questions during an interview are two different things. I'm not saying she's dumb, but reading a prepared speech doesn't make you smart or disprove your ignorance. I'll be interested to see how she does during the debate. I seriously hope she does better than in her interviews with Couric and Gibson. You can't watch those without cringing.