My thought is: "Any vehicle can tow anything. The question is how well can it tow?"
I've had several Tow Vehicles over the years.
1990 Chevy Blazer (2dr) 4.3L v6 High Performance Multi-Port FI
1997 Chevy Tahoe (4d) 5.7L v8 w/ Air Lift
2006 Dodge Durango (4d) 5.7L HEMI v8 w/ K&N FIPK Performance Intake System
2009 Dodge RAM Quad Cab 5.7L HEMI V8
With the '90 Blazer and '97 Tahoe, I had a 20' Four Winns 195 Sundowner. The boat pretty much maxed the Blazer out, I had a lot of see-saw, and I felt that something was behind me.
With the '97 Tahoe, It pulled like a dream.
Sold the boat and a few years later, purchased a Palomino Stampede 21RGS. The Tahoe pulled it great, sold that for a Durango (needed something newer and more reliable). Again, I felt the trailer behind the the Durango. Now I have a RAM and I never noticed the camper. Even now pulling my new White Hawk 28DSBH, I didn't notice it.
Now, all that I've stated will primarily due to TV wheelbase. if you compare the wheelbase between all the tow vehicles I've noted, the wider and longer the wheel base, the better tow experience I had; the easier it pulled, the more comfortable I felt, and probably the safer it was. This is only 1/2 the equation.
The other half is the power plant/Engine. A v6 will work, in most cases, but you may experience a lack of power as you go up a steep grade, and you may have some issues getting going from a dead stop. Put in a larger engine, such as a v8, you'll have more up-front power to get going off the line, and more reserve power for getting up those steep grades.
On a final note, I have unanswered questions and reservations about some manufactures putting v6 in a tow vehicle with a turbo-charger, and stating that it can pull like a v8. I have friends that pull long/heavy campers with such vehicles, and they eventually arrive at their destination. Like I first stated: "Any vehicle can tow anything. The question is how well can it tow?"
I've rode in one of these and haven't been impressed with the zero-to-sixty take off. My Durango w/ the K&N FIPK threw you back in the seat when opened up from a dead stop, or when it downshifted (there's the off-the-line and reserve power). where the other vehicle was sort of unimpressive. I guess the marketing of "Best in class combined fuel economy and towing" is just that? Maybe a sacrifice in towing capacity/capability for fuel economy?
I think I'll keep my 5.7L v8, install a K&N FIPK to gain the extra fuel economy plus get an increase of torque too.
That's just my 2cents, for what it's worth.