Could it maybe be that there is a misunderstanding of where "Stability" is coming from? Being as how we're talking leaf spring suspension anchored in the same place to the chassis on both SRW and DRW one would assume any stability difference wouldn't be impacted much by the sider axle stance, unless of course folks are picking up the outside wheel in the corners or actually sliding the corners, and given it appears most on this forum don't even tow in inclement weather I doubt that to be the case. Tire sidewall flex is a potential, but there are variable there to where it doesn't necessarily have anything to do with SRW or DRW.
Again, you want a suspension designed and operated within the parameters of the weights and conditions you'll be running in. If it isn't set up for the weight it will wallow, and feel unstable. To stiff and handling and vehicle control will be poor or anything less than smooth roads. My own thoughts are that it is the stiffer suspension designed for heavier loads that folks are liking the feel of and has nothing really to do with the DRW vs SRV portion of the design. Unfortunately, you have to give up significant handling and ride while unloaded to get the heavier carrying ability and capacity.
Personally, I've never agreed with getting too big a truck any more than I have thought to small a truck was wise. Get the right size for the job and try to minimize the inevitable tradeoffs.