2008 was a blowout election so I'm not surprised the Republicans improved in 2012. …
2008 was not a blowout.
Carriage of 28 states, which are 56 percent of the nation’s states, cannot be described as a “blowout.”
Blowouts include 1936 Franklin Roosevelt (carriage of 46 of 48 states) and both 1972 Richard Nixon and 1984 Ronald Reagan (both with carriage of 49 of 50 states).
Those are examples of blowouts.
2012 Barack Obama underperformed his first-term result with re-election. His high mark was Election 2008. Nearly everything afterward, while he held office, was reduced electoral support for the Democrats. (Exception: 2012 U.S. Senate.)
2008 was a blowout for Obama in some states, but against him in others. Obama won Michigan in 2008 by about the margin by which Reagan did in 1984. The problem was that he lost like McGovern in the Mountaqin and Deep South.