I would like to, as many others before me it seems, propose than an armor stand be implemented. I have several armors I switch between depending on the situation, as well as for purely decorative purposes.
I would like very much to be able to display these armors when not in use.
An alternative to a dedicated armor stand would be the ability to set a pose on a thrall, essentially freezing the thrall in that pose. And if not poses, then at least be able to set their threat reaction.
As the game is right now, it possible to use thralls as armor stands, but that only works until something gets within their threat range. Then I can spend time lining them all up again.