I agree that we should think about having the architecture generic with the synchronization connector/logic pluggable. That way Sync 2.0 could be used to synchronize into a central HIE infrastructure (synchronize patients with an MPI like OpenEMPI) for example, instead of a master OpenMRS instance - this is a use case me & @craigappl are interested in, more on this in Integration with OpenEMPI.
Implementing such a connector would require additional effort obviously, but as Darius mentioned, components such as FHIR based communication or the event feed could be reused in this case.