"I don’t think they can be a unifying force either because they don’t speak with one voice for one. They are self governing churches biased mainly on ethnicity/country and very independent of one another. Maybe one member of the communion could try but the branches can’t even all agree on the patriarch of Constantinople being the spiritual leader let alone some huge ecumenical work-sorry, I messed up the quote a bit
I think the Orthodox do speak in one voice albeit differently than the Catholic Church does. The relationship between the hierarchy and the laity are different in both traditions. While the Magisterium speaks with one voice, the laity seems to speak with another. Catholics in America seem to hold to beliefs that contradict Church teaching (homosexuality, contraceptives to name a few). They tend to adopt the spirit of modernity with its emphasis on freedom of thought unfettered by ancient traditions. In my fallible opinion, I think this is caused by how easy it is to become a member of the Catholic Church. Once you complete RCIA, you’re in.
In the Orthodox Church, what the clergy and laity believe are for the most part the same. Again, I think this has much to do with the process of joining the Orthodox Church which is harder and less structured than in the Roman Catholic Church. There is a long discerning process one has to go through even before becoming a catechumen. Then, you must wait for enlightenment, an encounter of sorts with the Truth that removes all doubt. Until you reach this point, I don't think a Priest would let you join (correct me if I am wrong Seraphim). My point being, no one can get into the Orthodox Church unless one believes everything it teaches to be true.
I think you will find this podcast by Father Thomas Hopko on the state of American Orthodoxy enlightening. He contrasts the unity of the Catholic Church with the unity of the Orthodox Church. ancientfaith.com/podcasts/hopko/fr._tom_reflects_on_kevin_allens_retirement