Has Vincent Sheheen shown any interest in running? He came reasonably close in 2010 in a Republican wave year, and McMaster probably doesn't have the kind of appeal that Haley did.
I'm not sure if Sheheen is interested in running... Although I think he too would have a good chance vs McMaster... there is probably a better candidate out there- and hopefully some good options will step forward if it looks like Master will not get a serious primary challenge.
And no- McMaster does not have any of the appeal Haley did... Even those who are not huge Haley fans would probably say that she was at least not the typical politician- and seemed to have decent sense of business and industry. Master (who will be 71 on election day) is seen as the exact opposite... nothing new & not especially intelligent.
But again- the big question is does McMasters get a strong primary challenge- and if so can he survive it (probably not on the latter question).