I wouldn't concede that much even, really. Gregory of Palamas (14th century) helped reshape a lot of doctrinal emphases. Also, despite how many E.O.'s nowadays consider Thomism to be a great heresy, the writings of Thomas Aquinas were actually quite popular for a little while in Constantinople. While Eastern Orthodoxy as we know it now was largely codified at the Council of Jerusalem (1672), there was a lot of Roman Catholic influence in many Eastern Orthodox regions in the 18th and 19th centuries. In Russia, there were a surprising amount of Jesuits teaching in the seminaries during those times. A lot of the current notions about Orthodoxy as some unchanging continuation of the Patristic tradition come from 20th century Orthodox scholars like Meyendorff, who were reacting to those western influences. But most people just aren't familiar with Orthodox history, so enthusiastic converts, their enablers, and outside admirers get away with quite a bit of romantic myth-making.