To be blunt, an important element of the 2014 midterms is positioning for the next presidential race.
If Republicans win the Senate, public expectations will rise for their ability to “get things done.” But with President Obama still in the White House for two more years, the best Republicans can probably hope for is small-ball stuff. Major immigration reform or tax reform is probably too much to hope for. It’s possible that a fully Republican-controlled Congress could put approval of the Keystone XL pipeline on Mr. Obama’s desk, and if he vetoed it, they might muster enough votes for an override.
But the main thing for Republicans would be to show that they know how to govern, and not just oppose things. And that could be difficult in a continued world of divided government – particularly if the far right really throws its weight around.