If the nomination process got out of the hands of the elites, it's possible. Palin is a hero (actually, a heroine) to a whole lot of Republicans who represent the most vibrant and vital part of today's GOP. On her own, she doesn't make gaffes. She lies, but she's a slick liar, and a lot of folks want to believe what she says.
In this polarized electorate, she'd lose, but not terribly. I think she would do no worse than Romney in 2012. I can't see a state that Romney carried that she'd lose. If events played into her hands, she could tip FL, OH, VA, and NH.
We are at a point where it doesn't matter a whole lot who the candidates of each party are. Hardened partisanship is at an all time high and increasing. Palin has a big following, and she has a hustle. She's experienced, and she'll never allow untrusted "handlers" to make her look foolish. She's a snake, but more than one snake has occupied the Oval Office.
No because she already looks foolish.
Never makes a gaffe? How about too dumb to even name her favorite founding father?