The October 2016 issue of the Joint Force Quarterly has some articles that shine some light on how our current Department of Defense leadership is looking at aspects of strategy for a 21st Century.

First, From the Chairman: Strategic Challenges and Implications

http://ndupress.ndu.edu/JFQ/Joint-Fo...-implications/

The Chairman identified 4 strategic implications:

1. The first one is foundational. We need a balanced inventory of joint capabilities that allow us to deter and defeat potential adversaries across the full range of military operations.
Not a new challenge, but it remains a significant challenge, more so tighter restrictions on the purse strings. The ability to wage non, unconventional, conventional, and nuclear warfare (I'm lumping cyber under non-conventional for now). While hybrid threats also are not new, it is still a useful concept for reacquainting the force with the totality of warfare. Before 9/11 is was conventional warfare centric, no need to worry about unconventional adversaries, after 9/11 the force swung in the other direction. Need to get after those terrorists, there will never be a conventional war again. We have started, and need to continue, to stop treating wars like Military Occupational Specialties (MOSs). One soldier specializes in conventional warfare, while another specializes in unconventional, and treat warfare more like liberal arts, than a technical trade school.

2. The second implication is the need for us to more effectively employ the military instrument of national power to address the challenges Russia, China, Iran, and North Korea present. Each of these nations, in different ways, fully leverages economic coercion, political influence, unconventional warfare, information operations, cyber operations, and military posture to advance their interests. This is competition with a military dimension that falls below the threshold that would trigger a traditional and decisive military response. And since these countries compete in ways that mute our response, they continue to advance their interests at the qualitative and quantitative expense of our own.
Back to the gray zone, a zone we compete in, but not as effectively as our adversaries.

3.
The third implication, and to me one of the most significant, is that we have a mandate to keep pace with the character of war in the 21st century.
Short discussion on multi-domain and rapid pace of change.

4.
Therefore, the fourth implication is the need for greater strategic integration in the future, both in our strategy development and in our decision making processes. The intent is to build a framework within which we can address these 4+1 challenges across the five operational domains with which we are dealing and the many associated functions.
This one worries me, because it is ahistorical and far being strategic as written. It continues to push the military-industrial-complex myth that if our technology enables us to dominate the 5 "recognized" domains, we will prevail strategically.

I did like the closing though:

What drives me, and what motivates our Joint Staff team, is the changing character of war. How do we get more agile? How do we frame decisions for our senior leadership in a more effective way? Just like every other endeavor in our profession, it begins with a common understanding of the threat, and a common appreciation for the capabilities and limitations of the Joint Force, and then a framework within which we could make real-time decisions that will most effectively employ that force.