In any case, she's not a candidate. Not yet. But right now -- even as a private citizen with zero representative power and essentially nothing more than a pundit -- she is the epitome of strength in her appeal and in her focused message. Her books are best-sellers (look at the Amazon numbers). She draws thousands at public appearances. She speaks and the world is interested in what she has to say. Guys like Romney are ambiguous, equivocal, fuzzy -- in a word, weak.
Palin is strong because her message is clear and her image is clear. You think independents want middle-of-the-road? You're wrong; independents and indeed Americans in general are SICK AND TIRED OF MIDDLE-OF-THE-ROAD weakness and ambiguity. It LOSES. Independents LIKE clarity and decisiveness -- it's why they voted for Reagan in droves, and why they remain singularly aloof to mushy moderates like Romney.
Meanwhile, if you are paying attention to the real world rather than the false picture projected by the entertainment culture and the MSM, you will see that Obama is LOATHED, hated, despised, held in contempt, by a ratio of about ten to one (often more) by those who make online comments on non-conservative news sites such as Yahoo News, LA Times, and ABC.
Obama's popularity is pretend, make-believe.
Well, how about Planet Earth? Last poll I saw nearly 60% would not consider voting for her for President and 37% of Republican voters wouldn't vote for her. A candidate can improve on support numbers in the polls, but those unfavorables are toxic.