In my opinion, the theory about rounded shoulders is based on fact. The real question, to me, is whether this is a factor in real life. With that in mind I try to prepare each, yes even the small hunting knives, for tough use. I make the tang as large as possible as it transitions from the ricasso to the tang and taper the tang sometimes drastically down into the handle.
Even if the tang is radiused into the ricasso, I dare say most will have file marks and deep scrathes perpendicular to the blade, which negates the radius by introducing stress risers. Not all makers will polish the radius and remove the scratches.
I am somewhere in between and take a little different approach. I set a limit as to how small I make the tang transition. I want my tang size to be no smaller than 5/8 to 3/4 the size of the ricasso. The more shock the knife is likely to recieve, the more I increase the size in relation to the ricasso. Here is a drawing of the ricasso area of a full tang and a hidden tang I did a while back.