In his defense, its rusty.
For me with that truck, I never needed a WD hitch, or felt I needed one, except one time:
I was driving back from the thumb area to metro detroit, so about 100 miles of flatland.
Had my 16ft tandem with my dad's Kubota on it. He looked up the weights and told me it was a little over 5000lbs, which was ok for my trailer. We couldnt' get the weight forward enough, though, because it had the forks on the loader, and they were already up onto the tongue, any further would have hith the tailgate in turns. The PTO-driven chipper was hanging off the back of the trailer.
That ride home we swayed pretty bad if we got over 65 mph. That was the only time I ever had an issue.
I also found his error in calculating the weights, he gave me the weight of the tractor itself, but did not include the front end loader, bucket, forks, chipper shredder, or account for the 5ft tall tires being full of water. I put us over 9,000lbs trailer load when I added it up.
I was just about ready to buy a WD hitch for my new F-150, but after towing my TJ, and my CJ8, both towed smooth and stable with just a regular ball hitch. But I probably will pick up a WD setup.