I think that harmony is the ultimate goal. Instead of asking if a golf course is natural, we should ask if it is in harmony with it's environment. And that includes a lot of elements that are not even necessarily golf related: the clubhouse architecture, the native terrain, the natural features of the land, the native flora, the community history and traditions, and the skyline, just to name a few.
Augusta is a club that engenders one of the strongest feelings of harmony of any club that I have ever visited, but most of the golf features are not even particularly natural (although everyone has their own definition for what is natural). Everything about the Augusta, from the entrance drive, the clubhouse, the glassy smooth wide-open fairways, the towering pines, the pine straw, the huge rolling greens, the magnolias, the cabins, even the aroma; all the elements complement each other. You don't have competing themes at Augusta, but rather one motif. And this is a very hard thing to contrive. It requires extraordinary personalities to design and preserve.