While the OP had asked about the appropriateness of saying "Most Divine," she had included the entire honorific, which includes the words "All Holy." Since then, I myself raised questions about using the entire range of honorifics, ranging from His Grace to His All Holiness." Some folks keep on pointing out that the GOA does not use "Most Divine" in English as if this settles the question. Is it or is it not true that the GOA refers to Patriarch Bartholemew as "His All Holiness," as indicated in the following GOA press release?:
"Ecumenical Patriarch Bartholomew to Appear on 60 Minutes Segment on Orthodox Christianity.
Dec 17, 2009
NEW YORK - His All Holiness Bartholomew, the spiritual leader of 300 million Orthodox Christians..." (my emphasis this honorific was repeated later in the press release)
For now, I will forgo a discussion of the oft repeated phrase "spiritual leader of 300 million Orthodox Christians." I will point out other uses of the medieval honorifics (or as Alveus pointed out to me, products of an ancient and venerable culture) all from the official GOA website: His Eminence Archbishop Demetrios, and Metropolitan Iakovos/Maximos/Methodios/etc., His Grace Bishop Andonios.
I am well aware that GOA is not the only jurisdiction to follow this pattern. Thus, we have His Beatitude Jonah, His Eminence Philip, etc... (Once, Father Alexander Lebedeff (ROCOR), after chewing me out royally on this issue, also pointed out senior priests also have a highfalutin honorific). Oh, I just noticed that the Church of Alexandria applies "His Excellency" to titular bishops, while the Patriarch is called "His Beatitude," which has a connotation of extreme happiness and bliss, in addition to blessedness. As an aside, Metropolitan Jonah certainly is a happy man and I think that we in the OCA have been blessed by his almost miraculous rise from Abbot to Primate in a matter of months. In any case, "eminence" is defined as "a position of prominence or superiority" in Merriam-Webster, which calls into question why this same term is applied to the Primate of the Greek Archdiocese and the bishops of the several metropolises under him (at least on paper).
Even if folks love using these honorifics as vestiges of a great past, I find the use of "All Holy" to be truly inappropriate. As far as I know, the following hierarchs are currently being referred as such: The bishops of Constantinople and Moscow (who is called His Holiness or The Most Holy used instead of All Holy, a distinction without meaning IMO). Think about it; even the Vicar of Christ is merely called His Holiness. BTW, such a honorific is also presumptuous, to say the least. But, hey what do I know?