About model and data exchange with 3rd party solutions: Revit, Solibri, dRofus, Bluebeam, structural analysis solutions, and IFC, BCF and DXF/DWG-based exchange, etc.
Nothing is "bound" to be lost. The new features in 4.0 shouldn't affect the translation logic, it's just easier to create certain library parts. One will never know until it is tried.
Is there any specific aspect of your question or was it just a general / theoretical concern lingering?