There are three major geopolitical forces in the world today.
Globalists, who are a loose network of people (not necessarily millionaires, even middle-class level employees) whose interests and daily lives are more related to global affairs than with any local problem, but which also include several multinationals, NGOs, Foundations, global governance institutions, media and so on. Globalists are not the billionaires only, much less the American interests, although many of the actual players are located in America, even occupying the American State for their objectives instead of American local interests. This loose network of people with different backgrounds is what paranoids often refer to as "Jewish conspiracy" or "American Imperialism", although it's neither. It's just a set of the population of the world that "thinks global";
Islam, a classic faith-based multi-national expansionist civilization;
Russia, the only classic nation-state that holds also classical imperialistic objectives;
It means that, despite much belief of some on the personal inspiration of some hierarchs of any church (Orthodox, Roman or any other), hierarchs are playing into the interests of one of these forces. God will surely guide the Church despite all this, but that does not mean the problem itself is a good thing.
The Moscow Patriarchate works with Russia for very obvious reasons. Orthodox Churches in the ex-communist countries face a dangerous dillemma of falling either back to the imperialistic Russian orbit, or into the Globalist influence of the European Union. Greek Orthodoxy has been playing with the globalists since the independence of Greece, while the Midle-Eastern patriarchates had to deal with Islam. So, the ex-communist countries, if choosing the European Union would probably slowly drift toward Constantinople along the 21st century.
Enviromentalism and Union of Churches are topics dear to Globalists. A multi-headed hydra needs a multi-headed religion, and multiple heads here mean less the number of hierarchs at the top, but the number of meanings the same symbols and words can have. In fact, having one supreme hierarch can only help in this standardization.
Current affairs are throwing the Middle-Eastern churches out of the influence of Islam into Russian influence. At the same time, Constantinople gets closer and closer with Rome in the globalist field. For Rome itself, that would be a perfectly good outcome: Orthodoxy split into two different grounds, a Romophile Greek Orthodoxy and Slavophille one, both hating each other, and claiming to be the "real" Orthodoxy. One could even think of a union of Greek Orthodox Churches with Rome, in which Constantinople would be given papal like powers over whatever churches remained with it in the Greek world, which an ambitious hierarch could agree. This block would have a tendency to "aggiornamento" while the block of Middle-Eastern Churches under the protection of the Russian Church would tend to stay more traditional in contrast to that. Rome probably would agree that the united Greek Orthodoxy kept calling itself the Orthodox Church and autonomous, so that, in its disputes with Moscow, they would prove that only a supreme hierarch can be the symbol of unity.
This is probably the scenario of Orthodoxy for the 21st century. If union happens with Rome, it will be this division with stronger colors and universal scandal among the Orthodox, for the ME-Moscow side probably would not follow the Greek churches. The churches in ex-Soviet countries would probably split among unionists and traditionalists or even form a "third way".
That is why I believe that even the wish for union is a bad, destabilizing thing. If union happens, it will not generate "one church", but the collapse of the sense of unity of both Orthodoxy and Rome (for also in Rome divisions would arise with several traditionalist groups not following and I would not be surprised if disputing popes appeared). It will not create a stronger sense of witness and unity, but just prove to the world that slander that the Church is just a human institution. Unionist ecumenism is just another revolutionary ideology seeking Utopia.
The Ecumenism that is possible and desirable, Dialogal Ecumenism, shuns talks of union and favors dialogue, fraternity and tolerant coexistence. And only that. A much better witness of belief in unity and love would be both Rome and Orthodoxy keep to their traditional ways and *despite* believing each other wrong, not initiate violence toward each other and show tolerance to converts. Orthodoxy would gather round the Symbol of Faith and the Holy Spirit, respecting the limited honours and duties of the Primate in Constantinople, and Rome around its supreme leader, the Pope. And the world would be a better place.