No doubt any high quality LT tire with equal or better rated capacity would indeed be an improvement over ST tires if you can go with a 16" rim. Our TT can be as heavy as 10K# fully loaded with water and toys, but most often we are averaging roughly 9K#.
We have been pretty fortunate as we have never had a blowout over the last decade using Maxxis ST tires, we do religiously replace our ST tires every four years and the Maxxis tires were starting to show the same issues that plague ST tires in general.
We even got 3 seasons out of the stock Chinese ST tires, but we went up a load rating from D to E when we installed our Maxxis ST tires. We always keep our ST tires filled to max psi which keeps them from overheating, we do travel above 65mph occasionally.
My brother and a couple of our good friends have tried the redesigned Carlisle HD ST tires with good results. Our neighbor had a new set of Goodyear Endurance ST tires put on his rig earlier this year, he likes them but states it's too early to gauge their overall reliability.