If you include a simple a VectorScript to the action, you may at least get the import dialog. VW is not particularly AppleScriptable, but it knows one word of AppleScript: Do Script.
A Folder Action? Maybe.
I run a lot of my generic utilites from FileMaker Pro with this overall approach.
However, one has never been able to "Open" a DWG-file with VW.
In 12.0 it wasn't that I could "open" a dwg, but with the automator action that I wrote, I could automatically import a dwg into an untitled window from finder window. This was particularly convenient.
I am definitely interested in what you suggest, but I have never worked with vectorscript and my apple script experience is mostly simple modifications to existing programs. I'll give anything a try though.
Thanks for the help.