Via Foreign Affairs daily opinion roundup:
Philip Stephens has an op-ed in the Financial Times suggesting that the next President will have significant continuities in policy with the Bush Administration, if only because there are too many problems to solve in the course of a single term.
If you allow problems to define you then I suppose he's right. I'd hope for more though, a lot more from whoever is next to sit in office. The key challenge Stephens dances around is rejecting the factionalism that developed under Bush and regaining control of the bureaucracies.
Throughout Bush's term he was constantly overwhelmed and outmatched by events on the ground. This was only partially due to his incompetence. Another factor was the lack of control and direction given to the bureaucracies that make up the federal government. Cabinet members and their subordinates were free to pursue whatever agenda they wanted, so long as they observed the Golden Rule: Do not make George Bush look bad. Disband the Iraqi Army? Give the leader of North Korea the finger? Badmouth Western Europe? Sure thing! Allowing the departments to pursue their own agendas meant allowing them to define their own problems, all of them vying for attention and resources. A more unified administration would force policies to match given resources, based on the President's priorities.
I think any of the current candidates including McCain would bring a more unitary style of management. That in itself would mark a dramatic change from Bush- a President defined by their policies, rather then their problems.