I think that like anything, the realationship of causes and effects in Iraq will be debated for a long time. I agree that there was no wholescale change in tactics, except possibly in certain local areas. The "surge" enabled us to more effectively execute those tactics in critical areas. Also, I think that beyond the simple increase of troop numbers, the surge represented a political statement of will to continue the fight in Iraq at a time when we were signalling transition and withdrawal.
Contrary to many accounts, the Sunni awakening and the emergence of CLCs ("concerned Local Citizens") was not merely a case of us buying off Iraqi tribes. If it were just a matter of money, we could simply keep paying for a long time. The cost-benefit case could be easily made between paying them and maintaining troops here. There were multiple reasons for this phenomenon, among them: extremists overplaying their hands, the relentless pressure of Coalition and Iraqi military operations (current efforts build off of previous efforts), and the signal from the surge that we were not leaving anytime soon (commitment to stay in Iraq).
Obviously, the history of the war is yet to be written. While we see the obvious temporal relationship between the surge and the improved security and can draw some initial conclusions, it will be awhile before we can have a deeper understanding of the cause and effect relationships at play over the course of this war. In the meantime, I agree with LtCol Gentile that any disparagement of previous efforts (as opposed to serious lessons learned efforts--which become progressively more difficult when you move from tactical to operational to strategic levels) does nothing to advance our effectiveness or capabilities.