I think you would find that we and the British are keeping most of these principles in mind with regard to these operations. Keep in mind though, that Musashi's principles are those of single combat for the most part. The Warrior as an individual with complete freedom of action.
In Afghanistan, it would be more appropriate to apply Clausewitz - War is nothing more than the continuation of politics by other means. Wherein politics decide strategy as much as military necessity. As distasteful as that fact often is, leading as it does to doing, or not doing, things that pure military strategy would dictate, politics and war are often insepparable.
Philosphies of military strategy can be roughly divided into two categories. The first would be those that apply to single combat or small unit actions, like Musashi. The second are those that apply to the conduct of wars in the larger sense, like Clausewitz. A big mistake I see made rather frequently is when someone criticizes our military strategy with valid, but mis-applied quotes and maxims, as if all could be applied universally in all cases.
There are two different view point on military strategy. One is that of a warrior, whose ultimate purpose is to win a glorious victory in a war. Certain warrior mores and mentality find their ways into their strategy. Its objective is to set up a one great victorious war.
On the other hand, the other is that of a ruler, who rules over his domain. In this case, it matters less on how glorious the win is as long as his army wins. He does not have to win a war if he can do it in other means. Or avoid it and still prevail. In this point of view, military strategy becomes combination of intelligence, sabotage, PsyOp, geopolitics, management of war materials, and actual fighting strategy itself. Sun-Tzu belongs to this group. His strategy is to deliver a (not necessarily military) victory in most efficient manner, which sometimes is not compatible to warrior ethos.
I am not sure where I should place Clausewicz. He is between the these two poles, leaning closer to warrior ethos according to my guess.