Combat absolutely should not be the deciding factor. It's been proven many times and by many people that lousy player-vs-player fighters can be competent and even excellent generals.
Achelous, Sonja and Elminster are a few of these.
Being able to fight players shouldn't decide whether your tactical savoir-faire prevails, or whether your military know how should be relevant. In fact part of the reason for warfare now being doable by duellists, and remotely from safe-rooms is to illustrate this point.
If people aren't interested in warfare then as I said - fine. However there is more than one way to find conflict, and as I have said many times now: it's phenomenally easy to prevent invasion at least in a short term capacity.
Warfare is fun! (And it's easy to learn)
Written by my hand on the 17th of Springflower, in the year 1290.