I may be missing something, but is there a way to re-project world (.wld) files, without hand digitizing to a new coordinate system? I am looking to do this specifically for .dwg files.
Take a look at this article:
How To: Define the projection for CAD data for use in ArcMap
It should help define how to re-project a CAD file (or really to project a CAD file, all you need to do is the same process with the .dwg for re-projecting, I would think).
CAD/GIS Data Integration
Retrieving data ...