Greece/Constantinople: Meletius Metaxakis and the Venizelist party in Greece were intent on reclaiming Constantinople for Greece. They wanted to appease the British (Anglicans) by adopting the Revised Calendar, who would in turn give Constantinople to the Greeks, (which never happened).
Alexandria: Meletius Metaxakis again wanted to appease the British (Egypt was a part of the British Empire at the time), and implemented the Revised Calendar in 1926.
Antioch: Wealthy Arabs among the Orthodox community (and Ba'ahists oddly enough), thought that the Revised Calendar would open up business opportunities with the West. Implemented in 1948.
Cyprus: Implemented in 1928, Archbishop Kyrillos III was basically strong-armed into implementing the New Calendar by the occupying British forces.
Romania: Implemented the New Calendar in 1924, to "accommodate" the large number of Uniates in Transylvania, which Romania had recaptured from the Austro-Hungarian Empire after World War I.
Bulgaria: Pressured into doing so, by the Soviets in 1968, as a test run to see whether the New Calendar could be implemented in the Moscow Patriarchate. When the only parish to resist the innovation was a Russian convent in Sofia (Convent of the Protection of the Most Holy Mother of God), the MP refrained from implement the New Calendar in Russia.