Hmm. Why would such an interface be a bad idea? Although, the only problem I can see here is if/when the user wants another type of Routing object à la "RedirectRoute". They would have to override this class - creating a little interface in the Doctrine/PHPCR namespace seems like a painless solution?

If we were to implement the interface I guess we would also have to determine the ID from either the DM or the metadata also.