I disagree: Oprah is a great candidate for President of the United States!
She's one of the greatest net-success stories in the world, coming from nothing and growing to be currently valued at $2.8 billion (comparable to Donald Trump, but she was given NOTHING so her valuation is more significant imho).
She attended uni on full tuition scholarship, has honorary doctorate degrees from Duke and Harvard, and is EXTREMELY educated.
She is a philanthropist, and as such works greatly to help those in need, and support those who are different, or trapped in this late-stage capitalist society. She's a proponant of equality, and is FIERCE.
What more could you want in a U.S. Presidential candidate?