I'm not confused. Been shooting sticks for nearly 70 years. During that time, I've shot countless ASLs of different lengths, weights, builders and models. I'm pretty confident that I can decipher different shooting characteristics when I encounter them. I mention the Taipan only for reference. Despite it not being an ASL, it's another of J.D.s bows that sports narrow limbs.
The tapering toward the belly you're talking about is called trapping (I offer the definition not for your edification, but for some others who might read this). It creates a trapezoidal cross section to the limb. There certainly isn't agreement among ASL builders and shooters as to whether trapping toward the belly or toward the back is better or even if a trapped limb has any benefit over a rectangular cross section in a glass laminated bow. (Of course, some builders trap limbs after the fact to make/reduce draw weight for a given customer.) I'm not saying J.D. does that. Trapping is a signature of his bows.
I find string material and brace height have a lot to do with the thump one feels at the end of the shot. A dacron string (vs a low stretch string) or a brace height that's too low both increase the thump at the end of the shot. So will out of time limbs, of course, even how the shooter grips the bow. There are lots of potential reasons for felt hand shock. Though my Berrys are gentle in the hand, they're no more gentle than my string follow Northern Mists. By comparison, my Jets have a bit more hand shock.
Howard Hill coined the term ASL -- American semi-longbow. If memory serves, his definition is on page 93 of Hunting the Hard Way. I no longer have the book, but to paraphrase, he described the ASL longbow in comparison to the English longbow. By comparison, he described the cross section of the ASL limb as rectangular, as opposed to the D-shape cross section of an English longbow. And in length, he described the ASL semi-long, again in relation to an English longbow which was longer.
Trapping doesn't define an ASL. And a limb width that's 1/16 to 1/8 inch wider than the narrower longbows being built doesn't
make it a flat bow. Lots of reputable ASL builders and shooters out there would concur, I think.
Regardless, you've obviously found a bow you like in JD's bows. I like them as well. However, that's no reason to trash other ASLs/builders. Your experience with hand shock may or may not be representative of "the rest of the world."