Models of the Jeep Cherokee, Pathfinder and others were effective off road and could tow as much as comparable ladder frame vehicles.
Yes they did have the same towing rate as a body on frame truck. If you towed only 2-5 times a year and didn’t always tow the max amount…then a uni-body is fine. But I sure wouldn’t want to be towing 4500lbs with a unibody vehicle that’s capable of towing 5000lbs (class III) 10-20 times a year with each trip being 100+ miles. I don’t think it’ll hold up nearly as well. My 98 pathfinder was a unibody. It was showing signs of towing stress when I gave it to my daughter and bought my 05 4runner. I town 10-20 times a year. Some trips were several hundred miles. The last year I didn’t take any long trips because I didn’t trust it.
My 4runner now has as many miles as my Pathfinder did when I gave it to my daughter…and it’s not showing any signs of towing stress. The body-on-frame is much more suited for towing and off roading.
A couple of big problems with unibody and off-roading…
#1 - Vehicle twist/flex. Not good for a unibody. If you don’t go crazy then a unibody can do fine. But you won’t find any deep expeditions with a unibody vehicle.
#2 - Inability to add a lift (at least not easily). You have to change out the suspension on a unibody. You can get some lift…but not much. With a body-on-frame…much easier and cheaper to lift. I agree lifting isn’t required for off-roading…but if you want to do some rock climbing or some deep-woods trails…a lift is a must.
#3 - I don’t car how good of an off-roader you are…things happen. And fixing a off-roading accident on a body-on-frame vehicle is usually a lot easier and cheaper then a unibody.
I will agree that 95% of people don’t tow that much…and don’t do any deep-woods off-roading - so a unibody SUV is fine. With my youngest going off to college in a couple of years…I think my towing will drop to just 3-5 times a year…and I doubt I’ll be doing much off-roading since my wife isn’t to mountain climbing as much as my youngest and I are.