Lower Your Expectations
When the CAD user looks at a PDF file in a viewer, (especially if the PDF is crisp) they see objects, intelligent objects. They see dimensions, block inserts, text and more. What they do not realize is that PDF files cannot contain these objects.
A PDF is not a DWG, it is a popular plot file format. The only content in a PDF is images, paths and text. There is not even a circle object in a PDF file, it must be represented as four bezier curves.