You are referring to an import/export for now? We don’t have a way to synch playback/record of the hosts (when one of them is Dorico) today do we? You can route the midi there, but recording is problematic unless you are doing it all in a “single take” with no edits or live instruments? I’d very much like to learn different. 
Even so, the other concern I see is the weight and uneasy truce of running two programs with their own audio engines. Is there a possibility at some point of Cubase and Dorico sharing a single instance of an audio engine? Not just sharing code, but a common service / VST Pool / IO etc? Has anyone else with both Dorico and a DAW up hit the “I’m sorry, but that file is in use by another application.” message?