My Thrall was sad a lot of people come to my discord asking what is the difference between my mod trader and “thespian” from Pippi.
I never had and I never will install Pippi. But now I know what is the answer. lol.
As for the topic at hand:
There is a way a mod can add vendors that the game does not like the ones in Sepermeru. They are set up by the table of dialogue and you can work them to function without strictly adding the voice things and etc, or use the ones already in the game. But they will work as they work in the game. They are flexible and you can really set up stuff in many ways, I am not not sure as to why the game does not offer them in more formats and why people who makes maps for mods and some other stuff just dont add them that way.
However, to add a trader that will work as a Thrall for people that are not in your clan, it takes a bit of “smoke and mirrors” to show something as a trade happening, but not happening codewise. And that might be why this “thespian” you speak of is a placeable, not a thrall.
I myself dont care about pvp when I am making my mods, and that is why I really just run over a lot of stuff in them. But I think there will be some work to be done to get a fully customizable Thrall that can work as a trader and still not conflict with some pvp stuff.
Afaik, that is the only thing that prevents the core game to simply have a thrall that performs the function of a trader, and as to why trading between players also is not a thing.