Having towed everything from tent trailers to a 14000# 5th wheel with half tons to 3/4 diesel I'd tell you there is a HUGE difference in stability and overall towing experience when you go from 1/2 to 3/4 ton. The HP/torque numbers are easy to get hung up on but it's really only half (or less) of the story. Bigger brakes, stiffer suspension and just a truck that's more suited to what you need it for.
Running a truck at the top of it's ability range is for guys who use their truck to get groceries 360 days a year and tow the other 5. If you're really going to put on the miles get the right tool for the job. Plus, as we all know, if the wife isn't happy.... nobody's happy :)
A 3/4 ton leaves you basically unlimited options for TTs.