I don't know...I'm not sure the difference between 3:55 and 3:92 is that big a deal "generally"....and notice I said generally. With the 6-speed trans in my 2wd '12 Express regular cab/short bed, I can select a proper rpm to suit my "empty" driving and my towing needs. I think these transmissions function quite well when you pay attention to trans temp and pay attention to not lugging the motor. I lived for about 300,000 miles with a GM 700-R4 and 3:42 gears for towing and off roading in 4WD mode by paying attention to the aforementioned issues, and this was not a very robust tranny. Keeping rpm at an optimum point by going between 3rd(regular driver) and 4th(overdrive), the tranny and engine worked less and lived longer. Higher rpm isn't always a bad thing up to a point.
I would agree that when you start upping the ante with even bigger tires and towing loads approaching the max for the given truck, the lower gears are better. Hotrodding a lower rear gear is also a pleasant benefit for optimum performance. My travel trailer is a hair over 5000 pounds fully loaded and ready-to-go, and my truck with 3:55 has no issue at all pulling it. Worst case scenarios usually only require going to 4th for a brief period which is about 2600 rpm. Otherwise the truck is usually loafing along. I can also see the benefit of the 3:92 when you're towing "and" you have a fully loaded 4-dr, 4wd, with all the extras and lots of people and lots of gear. Maybe there is no perfect gear, because there is no perfect, consistent situation. Things change.