It would be nice if you could auto-assign and/or update Items when the CAD file is checked in. At this point in my thought process, this would only need to be a global setting. Maybe some options for enabling or disabling certain CAD applications and file types would be handy.
Supporting iParts & iAssemblies in Inventor would be handy as well. But not so important, due to the frequency with which that would need to happen being much lower.