Hi,
I have to admit that there is much more work needed by Trimble to improve SU's export to CAD functionality. The situation has improved somewhat with SU 2017 release but there is still a way to go. If my practice was not heavily committed to Autodesk products then SU & Lo would be my weapon of choice for design work and working drawing production. Unfortunately, CAD remains the default in most Architectural practices here in the UK.
Are you able to share your SU or Lo file? What is your work flow? If your CAD guys are saying that your SU exports are not editable then that sounds like you are perhaps exporting raster images rather than just vector linework?
I use both SU and CAD on a daily basis and find that I can quite happily edit all exported linework in CAD. Getting the best results does require producing a highly organised SU model with all building elements isolated on their own layers. I found it helpful to create a SU template with an identical Layer structure as the company's CAD drawing template. Scenes can then be easily set up in SU to allow you to export these individual elements (foundations, walls, windows & doors etc) as separate dwg files. These files can then be imported into a CAD template to assemble the drawing as required. Think of the SU process as the equivalent of creating Autocad 'xref' or 'Writeblock' entities. Personally, I only export linework from Su using a simple style with all white background and all faces in the model displaying as white. There is no point trying to export using a textured style as the raster image will not be editable and the CAD guys will have to delete it or switch the image off in order to use the exported linework. Where hatching and shading is required, this will have to be done in CAD by your guys, with reference to a PDF version of the fully rendered SU drawing.
I highly recommend researching Nick Sonder and Mat Donley's book and youtube videos. Although Nick uses only SU & LO for his projects, he does include a process of exporting linework to CAD for his consultants similar to the way I described above. See also Michael Brightman's workflow. Michael's process involves a deeper layering structure and hence a longer learning curve but is equally as effective.
Sorry if all of this is teaching you to suck eggs, but as I mentioned above it would be easier to assist if armed with more information regarding your process or sight of a SU/Lo file.
Anyway, I hope that helps somewhat.
Good luck.