Why would they elect him in 2014 if they didn't in 2010? Just like Ovide Lamontagne in New Hampshire, Linda McMahon in Connecticut or John Raese in West Virginia...once a looser, right?
And by the way, Nikki Haley is awesome!
Now I see somewhat your point, but I think Sheheen, if he loses, would be more relatable to Harvey Gantt. That, and 2010 was a very strong year for Republicans, yet Sheheen only lost to Haley by 4, so I think he has a big shot at this, particularly because polling shows him up on Haley 47-44.
Now, the candidates you listed were basically perennial type candidates: candidates that had enough money on their own to run again and again, I don't think Sheheen is that.