The Tower Unite workshop SDK is backed by ModelCompiler.exe, ModelViewer.exe, and model.dll. These are raw binaries with no debugging or library linking symbols, and the plymodel format is also completely proprietary.
My suggestion is either making these tools open source or providing a .lib file for model.dll so people can develop tools to work with compiled models (this is an alternative to providing the full source, just giving function definitions so others can use the library). Currently, there is no way to “decompile” a workshop model, or even modify it in any way (say: modify a material/texture).
As a fan of reverse engineering and file forensics, I would find immense interest in the actual format of plymodel files - it seems they contain their own custom model format, and then embed multiple PNG files for texturemaps, normal maps, etc. At the current moment, it is impossible to decipher what is actually happening because compiled C++ binaries are a huge pain to reverse engineer.
It would also be nice if these tools were distributed separately with documentation instead of packed inside the game and hidden in the files.
IMO this would allow more community innovation relating to workshop if people were able to create their own tools and also modify / disassemble existing models.