I have never used a M torsion bar trailer. But, I borrowed a torsion suspended trailer a few months ago. 26 foot box trailer to haul a M715. The trailer had a max gross weight of 9K. I know there was at least 12-15K inside that thing. I rode a little lower for sure. But, the tires weren't leaning in, the suspension still suspended and it pulled great.
That was my first experience with non tube axle trailers and I was impressed. If I ever need another trailer and have a choice, I would suggest torsion suspension. Not near as many moving parts to wear out during normal use either. Plus, I didn't try this, I imagine if a bearing went a hub could be pulled and an empty trailer still pulled without the opposite tire leaning in and the tire on the same side up in the fender.