This point of view strikes me as strange considering how D&D came out of wargames in the first place and incorporated the idea of "graduating" to a leadership position in its earliest incarnations. I think it is more accurate to say that over the course of the editions, particularly in the WotC era, the focus of the mechanics as moved ever more onto the "combat board game" as you put it. Early D&D had far less mechanical focus on combat as a percentage of pages in the book or whatever metric you want to use. D&D was about exploration and treasure hunting and character advancement and eventually building a keep and gaining followers.
That said I am not really interested in arguing about the basic premise of the thread. I want to talk about how to do it and how to make it fun, not whether it should exist at all.