This reminds me of one of my early remodel projects where the club president looked at a dogleg left, and wanted the fw bunker on the left saying it was philosophically correct. The next hole was a dl right, and he again suggested a bunker on the left, again thinking it was philosophically perfect. When questioned, he turned to me and said "Isn't it true that you usually guard the "long cut?" His real philosophy was no bunkers on the right because he sliced, and all bunkers about five yards past his normal best drive driving distance.
When I used outside fw bunkers, they were more target bunkers to aim at. They seemed to be useful on the left side of the 1st hole when seen from the clubhouse, for example.
Occasionally you can use an outside the DL carry bunker because the green opens up from the outside of the DL. Riv no. 3 is an example. It usually takes a strong hazard like a pond or a tree on the inside front corner of the green to force golfers to not play the shorter inside of the dogleg route, because that is how strong the inclination is.
Hogan was quoted as saying there should never be a bunker on the outside of the dogleg, and philosophically (and ignoring both potential aesthetics and/or combinations of bunkers that set up something on the tee shot) correct. But, as we always say here, it's about fitting the site as much as anything. If one more outside the dogleg fw bunker gets built, even if you are strongly against it, no animals were hurt in the building of that bunker, the world goes on much as before without spinning off its axis, and it's not really that important in the big scheme of things.