All I can contribute is that I rented a new 2004 Dakota QC with 4.7L V-8 and 5-speed auto, when my 92 Dakota was in the shop. I drove it 240 miles in 3 days, commuting, so it's consistent with the way I drive my 92.
My 92 gets 19-20 mpg highway on this ride. The best I could squeeze out of the 2004 was 17 mpg highway. It did ride exceptionally well, it was like a sofa on wheels, very car-like. But then again, for a 21-yr old truck, my Dakota rides beautifully.
Shifted fine, handled fine. Power felt about the same in that heavier truck as with my 92 with V-6.