Let's see, I've been towing trailers almost on a daily basis since I was 16, up until recently of course.
I towed with ALL half ton trucks when I was mowing lawns including one entire summer with an F-1Shitty towing 3 riders on a landscape trailer, with a bed loaded with hand tools, 3 weedwackers, 3 blowers, etc.
My halfton truck towed my jeep FINE at 85 mph +. I towed my jeep a total of 20-25 times in the last year. I bet combined with my trailer the whole shebang was 6000-6500 pounds.
My boat, fully loaded on the trailer I estimate at 4,000-5,000 lbs. I tow it at 85-90 mph on the freeway, I've towed it to the point the truck shuts down (right around 100). I weave in and out of traffic like an asshole, I accelerate from stop lights with my foot on the floor damn near, and I wait until the last second to hit the brakes and signal.
I do not have trailer brakes on either of the trailers discussed above, I never had a situation where I had excessive sway on the truck or the trailer because of my suspension that was designed for comfort. I never had a problem braking, I never had a problem accelerating.
A diesel 3/4 ton is NICE there is no doubt about it. But a diesel 3/4 ton is NOT necessary.
I've towed with 1 ton diesels, 1 ton gassers, etc.
Perfect example, hoser's 2500 HD with 8.1 GAS monster towing my boat, it towed the boat FASTER then my half ton, but stopped no better and rode like a hay wagon.
If you are not towing every day, and you are not towing more then 7500 lbs you do not need a diesel, plain and simple.