I'll try to be brief, although doing so is fundamentally difficult for university professors.
The Canadian Forces, or the army in particular, asks itself this question every day when it comes to structuring training courses in the combat arms. The response they've come to is the same one that I as a detached observer would recommend, looking at both the recent history and taking a longer view of the past, and that is that good counter-insurgency doctrine and training for armies, navies, and air forces is virtually the same as good doctrine and training for multi-purpose forces that are ready for any kind of conflict in the conflict spectrum, including peace-building, peace support, and stability-building operations, because the very same practices and the very same soldier skills, sailor skills, and air crew skills that are required to fight a counter-insurgency war or a high-intensity war against an equal enemy, or to conduct a peacekeeping or more classic peace-building operation, are the same. The level of violence, of course, changes the way in which one applies deadly force, but the necessity to have the basic fundamental skills required of a fighter squadron, a warship, or an infantry company to be able to destroy the enemy or neutralize its movement are the same.
So the argument in the army is to train the way you've always trained and add mission-specific components as necessary.