Text in dwg-files must not overlay walls or ducts in the Revit model.
Every time we have to clean up the dwg-files (eg. as an architectural underlay) from texts. Otherwise sometimes we hardly could see our ducts and other installations. If texts in Revit are on top of all other things this is just fine. These texts are used to describe the ducts and other installations (in our case).
But at least there should be an option to put the texts in dwg-files to the background.