It goes without saying that the closer a towing combo is to being maxed out the less desirable the towing experience. Towing comfort while underway is different from one driver to another. Some have no qualms pushing the limit and are plenty happy with their results, after all they got to where they were going. Others go to the opposite extreme to have that feeling as if they weren't towing at all, their choice, their money.
Todays half-tons offer some pretty impressive towing specs properly equipped and there are plenty of RV manufacturers pumping out lightweight rigs that in-themselves are pretty impressive with all their amenities. If you go with a 3/4 ton you will be able to tow pretty much any TT available, many of the heavier high-end TTs have the same floorplan as their 5er counterparts on a single level deck, although storage isn't as expansive.
We have a Chevy 3/4 ton gasser with 4.10s to haul our 33' 10K# TT around the four corner states, nearly all of our RVing is above 5K' elevation where a gas engine's power is derated 3% every 1K' of elevation. IF you decide on a gasser don't be afraid to let her rev up as they are designed to do just that in order to reach their power band. Going up the many inclines in our region, our gasser happily roars into life to carry our rig where it needs to go.