Without going into historical issues (such as Chalcedon) that were discussed before on the forums, look at other issues that cannot be neglected in pursuing unity. I will try to be as balanced as I can and try to look at the issues as an outsider. Consider for example:
- Who will have jurisdiction over the dioceses in West ? These are very important dioceses for evangelism and for resources. While Egypt and Syria will not be disputed and the Balkan and Eastern Europe will not be challenged, the remaining West is open and has congregations of immigrants that cannot be neglected in number and in influence. According to Apostolic laws, you can have only one Bishop in the diocese.
- The relation between H.H. the EP and their Holiness the Patriarchs of the OO Church is also a sticky issue. OO do not believe in Supremacy or Primacy of the EP ( or of Rome ) and the EO definitely do. Will the Patriarchs of the EO accept that they submit to the EP while their equals on the OO side do not ? This is a faith issue, by the way, and not political.
- There are controversial figures on both sides that were not excommunicated by either Church but whose teachings are very suspecious and are not short of heresies. I am NOT talking about the figures of Chalcedon, I am talking about contemporary writers, "theologians" whose Orthodoxy is challenged based on their writings. If you unite both churches, these figures will be acceptable in the other circle and this is a great danger. Their writings will circulate on both sides. In fact, this is already happening based on the common declaration of faith.
- Both sides believe that the Church is infallable. How would you explain the schism if neither side will confess any error and will hide behind the word "misunderstandings" ? If the Church can err once, why can't the Church err again. It will prompt a new wave of revision the Church teachings and history. Unity is not worth that for either side. We are talking about a list of saints, a list of councils and a list of writings that make up a huge part of the history of both churches.
- Take the issue of marriage for example that is overlooked by the OO in unity talks for unknown reasons. EO, as far as I know, bless marriages between EO and non-Orthodox "christians". OO do not and oppose such marriages. This will result in OO running to EO churches, after unity, to marry non-Orthodox because the OO churches will not allow such marriages. The run-awat OO would be considered a faithful orthodox by the EO , and can take communion, where he is regarded as an unrepented sinner, living in adultry by the OO church and will not allowed to commune.
- Both churches are facing severe conditions. Islamic terror is on both sides, Protestant infiltration, morally liberal movements insdie and outside, .... etc. There are more immediate needs that have to be fulfilled and clear and present dangers that take priority over unity talks. I do not blame either side. One might argue that unity can be a force against non-Orthodox movements and teachings, but it can be also argued that based on historical facts, the unity might introduce more problems.
Note that the above mentioned severe conditions need powerful politics, something both church lack. In short, neither side offers any political "protection" to the other, in contrast to a unity with the Vatican, for example, who have everything except the Orthodox Faith. May God protect both.
- H.H. the EP, who is behind the unity and one of its main advocates to my knowledge, does not seem to command enough support from other influential Patriarchs on the EO side. That does not help.
If you add the historical issues to the above points and the faith-related conflicts, it is a difficult way and maybe not beneficial for either Church.