This feels like a very inadequate response to the questions at hand, but perhaps two approaches may be useful.

First off, there is a cultural issue here, and it is not just the Personnel system, it is a true American military cultural issue, namely that of the relationship between the political and the military. This is perhaps flogging a dead horse until the hide comes off, but there is a real, hard separation of the "political" and the "military" in American political/civic and military culture. Politics, which is the matter that Strategy derives from, is (formally) kept at an exaggerated distance from the military, and vice versa, and one effect of that is to insulate military thought in general and the professional consciousness of the officer corps in particular from political considerations.

Make no mistake, I am in no way proposing any change to the apolitical status of the military. But if you look at Commonwealth militaries for example, there is quite a different "professional consciousness" at work. The officer (and even the NCO, especially the senior NCO) is acutely aware that he is not only the instrument, but even the direct agent of his Government's policy. He just happens to implement his Government's policies by primarily military or para-military means. An officer in a foreign land is not just a military professional, but even a sort of minor plenipotentiary, with both the duty and the authority to make local deals with local authorities - unless overridden by his own superiors. The implementation of policy, not simply the completion of a mission or the achievement of an objective, is what ultimately matters.

The US Army has had a good deal of experience doing this, and not just in recent years, but throughout the past as well. But there is at the same time a strong professional aversion to political matters, and likewise a strong professional preference to stick as much as possible to military matters and tasks. In the Commonwealth, no such division between the political and the military is culturally possible; officers are always subordinate to their political masters, but are always aware of the primacy of the political objective, and peform their military tasks with that foremost in their mind. To put things another way, while Commonwealth militaries have a history of difficulty with the Operational level of war, they tend to do rather better at the Tactical and Strategic levels; the US, on the other hand, tend to do rather better at the Operational level, but tends to run into problems at the Strategic level.

Secondly, and this is something that periodically raises its head from time to time, is discussion of creating and establishing a true General Staff system within the US Army. There have been political objections to such proposals in the past, but perhaps a permanent, specialized General Staff branch (as opposed to the present Staff branch system, which on the surface appears very akin to a General Staff system, but is not quite so) might provide for a solid and institutionalized cadre of strategic, operational, technical, and other specialists that are fully integrated at every level from Battalion on up.

The General Staff Corps would, in addition to providing the intellectual backbone of the Army, would also act as a sort of Institutional memory bank, so that lessons learned would not only be collected from right across the Army, and then digested and re-disseminated throughout, but also preserve the lessons learned so that they would not be so easily forgotten, and have to be re-learned later.

A fair bit of change, needless to say, would be required within the Army to make a true General Staff system an effective reality. The service colleges, along with capable faculty, exist, as do capable officers; they need to be released from artifical constraints and be allowed to truly excell in order to reach their potential. Perhaps service colleges might need to be amalgamated in order to provide a more centralized and unified base for the education and maintainenance of a General Officer Corps, and perhaps making a much clearer differentiation in content between Branch Advanced Career Courses and CGSC would be a place to start; right now, they seem to duplicate a little too much of the same content.