Yes, I also have read the marketing hype from both Goodyear and Michelin regarding true RV tires and the supposed advantages over "truck" tires.
However, I have been completely unable to find any independent verification of those claims. On the other hand, these are the also the two tires with the largest number of complaints about quality and etc. It does make one wonder if there is any correlation between the "soft" rubber and the reported issues.
From personal observation my original Toyo tires were 10 years old when I replaced them with Hankook and the ride and handling improved dramatically. Granted comparing old tire to new tires is not particularly valid. My new coach came with 3 yo Toyo and they are noticeably stiffer but still acceptable. I think this is sidewall difference but could be the compound as well...no way to tell.
Until there is some verification that "RV" tires perform as well or better than "truck" tires I will stick with what works....and incidentally pocket the significant $$$$ difference.