What's also interesting about this election is Repubs only faired well in one area... The House. After the last election, congressional district lines were redrawn, and in a way favorable to the Repubs who won heavily in 2010.
They lost ground in the Senate... and Romney lost, despite Obama getting millions less votes than 2008.
Republicans lost the popular vote in the House, so gerrymandering might be papering over the cracks a little. It'd be dangerous for the Republicans to look at their House majority and say everything's fine.
Yeah, the way things are gerrymandered (wide Dem districts, narrower GOP districts), the GOP's hold of the House will get crushed in a wave election that is pro-Dem. The GOP apparently learned nothing from 2006 and 2008. 2010's gains were a combination of a wave and getting back two waves.