I remember having a convesation with the Metropolitan of Lebanon decades ago, who said that this is one of the things holding up the reunion "because no one wants to die." The Arab Orthododox in Greater Syria (there isn't even a proper OO Patriarchate of Jerusalem) outnumber the Syriac Orthodox, and the Copts overwhelmingly outnumber the EO (Arab and Greek) in Egypt herself. The problem is that Alexandria not only represents Egypt, but All of Africa, where the numbers change.
One hears talk in Syria of when one of our Patriarchs of Antioch (both in Damascus, falls asleep, EO or OO, the Holy Synod will not elect a successor, and the unification will begin. That would be possible if (and I am not wishing this by any means) HH Ignatios Zakka I Severus passed first, given the difference between the set up of OO Churches versus the set up among the EO Churches. The others in the EO Communion would be the hold up here.
In Alexandria, there is a different story. Both Churches get along fine as of late. But the EO do not have a native hierarchy, which casuses a different dynamic: the Church is run with imported hierarchs (who have no vested interest in the OO, coming from relatively OO free Greece) on a continental (i.e. African) rather than country (i.e. Egypt) scale. Alexandria's OO daughers in Ethiopia and Eritrea are autcephalous, more or less, the EO there not at all. Pope Shenoudah has seen several EO Popes (all foreignors) come and go. There was no talk as far as I know about not electing successors, and given the foreign hierarchy/continental view, I'm not suprised. On the other hand, the Copts have jursidcitions world wide (but still Egyptocetric). So who would end up Patriarch of Alexandria remains a question.
The EO Patriarch would remain by default, but its ethnic problems would rise.
The problems in the "diaspora" would come home, as several EO territories have OO minorities. The Armenian Patriarch of Constantinople would be repositions, the OO hierarchies would be ammalgamated in Jerusalem, the Armenian bishops of Syria would become members of the Synod of Antioch (I'm not sure of their present status).