I dunno… The GOP is like a dog with a bone where conspiracy theories are concerned; I think Benghazi has the potential to be the main focus of their anti-Hillary campaign. Besides, they have the potential to blame her for everything Bill did wrong (Lewinsky, and so on), and for every little nutcrack from her past.
Although she's the most popular contender among Democrats, she's very bad for progressives who are feeling buyer's remorse over Obama. Sanders or Warren would be the best choices but they're too busy holding off the tide of corporatism in the Senate to run for office.