I'm not a huge fan, but I have some hopes that he'll be a relative dove without being a knee-jerk quasi-isolationist. Even if his only major initiative is purging the right-wing extremist military-within-a-military he'll probably be the best, or least bad, SecDef in my lifetime, just like I expect Garland to be the best AG even if he sits on his hands for four years.
True, but relative doves tend to get shoved out of the window under any pressure. Remember how much effort it took to get Chuck Hagel installed, and how quickly he fell out of power and was swiftly fired?