There are a multiplicity of Constitutional Officers up for election this cycle, including open seats for Governor, Lt. Governor, Superintendent of Education, Attorney General, and Adjutant General, plus a replacement Treasurer who hasn't faced a general election for the post, though I believe he is the only declared candidate. (I've seen rumors that the Comptroller General Richard Eckstrom might not seek reelection to a third term, but I don't have any basis to judge them by.)
With five open Statewide offices, and Spratt standing an excellent chance of being redistricted out of office by the 2012 cycle, it's no wonder that the SC-5 race will likely not get a local Republican push. It may get a push from the national GOP if State Sen. Mulvaney can improve his poll numbers versus Spratt during the primary.
Why will Spratt get redistricted out? With the Republicans gaining a seat, the smart thing to do would be to make the new seat safe Republican and keep Spratt's district as similar as possible so they can still win it when he retires.
Oh, right, "smart thing".