For example an EASA license issued in Germany will be good for an N-reg in German airspace but won't be any good for the same N-reg in UK airspace. There are two FAA OCC opinions out on this already so I consider this old chestnut done and dusted.
Nope. JAA licences were licences issued by NAA in accordance with a set of rules. If you followed the rules to the letter you were a member of the mutually recognised club but nonetheless each licence had a separate state of issue.
An EASA licence will be a single EUROPEAN licence subject to a single European equivalent of the ANO. Very much in the same was as an FAA certificate is federal certificate instead of a state certificate.
So a single EASA licence has true European coverage.
It is this very thing that is preventing the adoption of an IMCr as an example, it is either an all or nothing situation and is the reason EASA are able to mandate an EASA licence for operation in it's airspace.