GWToolset is a maintenance burden, that no one really understands or works on...
It is duplicating a lot of the functionality that is being re-implemented in FileImporter...
I wonder, how much would work it be to reimplement the extra features ontop of FileImporter (probably still keeping it as a separate extension, but reusing Move-Files-To-Commons's file copying features etc
GWToolset targets a very different audience with very different needs. It's true that the two projects share some technical requirements (transferring files including a lot of metadata to commons). But a lot of the code in the FileImporter extension does not apply. I would suggest two possible routes for a future project that might pick this idea up:
You could also look at the FileImporter as an improved version of the upload a file from a URL already in core.
It would probably be possible to squish the extension into core? or perhaps it better stay as an extension but plug into the existing url upload functionality?
Ways to then extend the more advanced upload / import process provided by FileImporter could then be added?