Gen Mattis
“I believe the single primary deficiency among senior U.S. officers today is the lack of opportunity for reflective thought,”
Sorry, but it's not the lack of opportunity, but the out right lack of effective thinking, even given the opportunity! Look at the garbage pumped out by those who have ample opportunity.
“We need disciplined and unregimented thinking officers who think critically when the chips are down and the veneer of civilization is rubbed off -- seeing the world for what it is, comfortable with uncertainty and life’s inherent contradictions and able to reconcile war’s grim realities with human aspirations.”
Again, I submit it's actually more effective to have done the thinking, before the "chips are down." Comfort with uncertainty comes from confidence. You can walk in the Valley of Death because you "fear no evil."
I fully agree that the problem comes from a lack of discipline. There simply is none in the thinking that informs most military debate. -

In fact, in some limited way, this forum represents some of the most rigourous thinking on the subject - yet no one here would be widely recognised as one of the "leading military thinkers."