Thanks everyone for the comments and advice. I'm surely taking note of all of it.
But for now, a WD seems in my case a solution in search of a problem. So far the "experts' at Camping World says I don't need it and in Toyota too. In fact, I kept on hearing that I found a sweet spot for a camper-trailer and tow vehicle combo -- and I'm beginning to believe it with it's handling in 50mph crosswind at Cajon Pass in CA I-5, the steep Grapevine 6% grade up-downhill also in I-5, the buckling at the ancient wavy I-10 inside LA which I immediately able to control with slowing down and the more than 100 hair-pin curves in icy road in Highway 120/140 from Yosemite.
And yes, I don't intend to add more weight nor drive thoughtlessly with my family with me.