If not for Democratic opposition to the War in Iraq and the American people voting Democrats into office, there would be no surge. Had the Republicans maintained control of Congress, Bush would have stuck with Rumsfeld. Bush did not dump Rumsfeld and switch strategies because he thought he had done anything wrong or because he trusted McCain's leadership and judgement. He did so because the American people demanded a change by electing Democrats who would oppose the failed policies Bush had pursued in Iraq.
So while the surge has turned out better than many (including me) predicted, opposition to the Administration's conduct of the war is the only reason the surge ever came about in the first place and no one need regret that opposition.