I'd put cunning first, strength nearly last, though. Putting strength and endurance on a pedestal means they become the hammer waiting to be used. Hammers tend to demand to be used, and projects that need other joints get nailed instead.
Cunningness means nothing if Joe can't make it to the objective. Although strength plays a role, endurance is the key. Not only of the body but the mind. Cunning will not get you through either Ranger school or SFAS, nor should it. I don't give a damn how cunning Joe is if he cannot keep up, or if he cannot pull his weight while on mission.
As for projects that need joints instead of nails.....are you or were you by chance a leg? I ask because that is the objection of many soldiers in leg units. But it's pure B.S.
While leg units usually have months to prepare for combat, the 82nd, Rangers, SF and D-boys do not have that luxury. So it only makes sense that resources are provided to those units expected to be in a high state of combat readiness at all times.