I found this piece posted regarding the role of civilians in Aussie military debates. It does a nice job of arguing why civilian folks might just have both different and valuable perspectives to bring to the table even if their military experience is minimal. Civilian strategists might not have much to contribute to tactical matters (how to fight a particular battle) and just a bit to operational planning (what the military should be military should be doing this month in Helmand. But for questions about whether the effort is worthwhile, what are the political consequences at home, in the field and farther afield, how we might evaluate the tradeoffs, and so on, civilian experts provide a valuable perspective.
War is too important to be left to the generals, as Clemenceau apparently said. True, too many cooks spoil the broth, but good decision-making requires a variety of inputs. The problem is that any one unit has a distinct culture and shared set of experiences that is likely to limit the diversity of views. Involving outsiders is a good way to have a check on that. It does not mean that the civilians are always right, but having to answer their concerns is a good way to force the military to think a bit more about their assumptions.
Of course, the MacArthurs and Tommy Franks of the world will not listen, but, luckily, not all military leaders are as impervious to insight as these folks are.