Going back to the original question, yes Carlisle Radial Trails are better then what you have.
The ST tires Carlisle sells today (Radial Trail RH or HD) are a vast improvement over ST tires Carlisle sold years ago. I have over 7000 miles on the set I have now with no issues.
The advise to "buy LT tires", without a model attached to the advise is dangerously bad. There are LT tire models that should never be used on a trailer.
There are LT tire models that work well, maybe better then any ST tire. An example is the G614, which is an LT tire.
Where you could go wrong is getting a deep lug, high traction, "off road" LT tire on your trailer. You actually don't want high-traction tires on your trailer.
The big downside to G614 tires is that it's common for trailer rims not to be rated for the higher PSI (110) these tires are rated for, rims and tires can run $450 to $550 per tire.