...i think that you have said it well, and would add the following comments...

...you can usually add an extra pair of 20 gauge smooth bore barrels to most 9.3x74r actions to make for a true 'one gun' kit for world-wide hunting exploits...

...for anything less than big bore dg doubles (read .450ne, .470ne, etc.), i also believe that the 9.3x74r is the way to go for the reasons that you have suggested...some additional reasons include the ready availability of ammo and brass (as opposed to, say, the .375 flanged), the fact that the cartridge uses a rimmed case and the mild recoil that most 9.3's are able to achieve (thus assisting in sight acquisition, aim and followup shots)...

...having read the literature (especially 'the perfect shot' by doc robertson (?)), looked at the ballistics charts (especially norma's charts), and used the cartridge in the field, i believe that the 9.3 is a superior bullet sectional density-wise, and may well achieve superior results and ballistics (especially penetration) at distances in excess of 100 yards (when compared to, say, the .375 flanged or even factory loaded .375hhs)...

...just some personal observations...