When the weight of your TT approaches the towing capacity of your truck, you lose a margin of safety, especially with a short bed. Towing an RV is supposed to fun, so I like lighter trailers.
Light trailers end around 5,000 pounds. But it depends a lot on the type of roads you drive. The interstates are one thing, but the back roads in the West are quite another. I like the back roads because there is a lot to see. but they are steep, banked the wrong way and often have no guard rails. Some of them are dirt, and some of them are rough dirt. The bigger your rig gets the more of those routes become off limits.
People talk about towing 10,000 pounds or even 15,000 pounds. Maybe that works for RV parks and state highways but not so good for boon docking with no one around.