Actually, the guy is taking a fairly conservative position by arguing against both global and supranational currencies. The Euro is doomed because there is no central structure, hence no fiscal discipline by most of its member states. Unlike the individuals calling for increasing amounts of money printing in order to save the sinking ship, (e.g. Bernanke et al.), Rogoff maintains that the monetary system is inevitably fatally doomed.
He doesn't go down this path, but one could effectively use his arguments against countries who attempt to peg their currencies against other country's currency for an extended period of time.
Personally, I enjoyed the article. Thanks for posting.