Among the various Greek Catholic Churches this feast is Vigil Rank.

For which Churches is the Pope the Patriarch?

Patriarch of the Russians?

Patriarch of the Ruthenians?

Patriarch of Skopje?

Patriarch of Addis Ababa?

? ?

The Pope of Rome exercises patriarchal functions for Eastern Catholic Churches without a Patriarch or Major Archbishop. So the Pope does function as Patriarch for Ethiopians, Carpatho-Ruthenians, Slovaks, Hungarians, Croats, Italo-Greeks/Albanians, Serbs, Macedonians, Bulgarians, Greeks, Albanians, Russians, and Belarusians,

For which Churches is the Pope the Patriarch?

... These texts in the Uniontown Menaion do indicate the Immaculate Conception and the Latin theology underpinning it.

So would we say that the "upgrading" of this Feast from Doxology to Vigil is in itself a latinisation and the Feast should return to its ancient ranking?

The Immaculate Conception is Catholic dogma not Latin theological speculation. What words/terms do and which do not satisfy a true Eastern articulation of this dogma? Is just saying the pertinent words-- conception, immaculate -- automatically "Latin theology." It would seem then that the discussion is over before it can start. As Catholic dogma -- truth -- pravoslavnych (for us) in the basic meaning of the word, there surely must be a legitimate Eastern articulation both liturgically and theologically. Eastern theological terminology would be deficient, bereft of full expression, if it were incapable of doing so.

St. Mary’s Immaculate Conception:

Some Church fathers do not believe Virgin Mary to be without faults, such as St. Irenaus, Origen, St. John Chrysostom. However, these opinions do not represent the widespread Mariological Tradition of the early Church.

We believe that St. Mary’s holiness is unique and surpasses heavenly creatures; she passed all her life in holiness as the true Ark of the Covenant, which was made of incorruptible wood laid with Gold from inside and outside.

The Orthodox Church, whose love towards St. Mary is deep-rooted, considers her more holy than all the heavenly creatures, whilst a natural member of the human race.

We do not set her apart from the human race by assuming that she was born without original sin (immaculate conception), as if she was born of no human seed. Thus, the Church makes a distinction between St. Mary’s life before and after the moment of Divine Incarnation.

St. Mary herself declared her need of salvation when she said, “my spirit has rejoiced in God my Savior.”
(Lk 1:47)

This Orthodox concept preserved our Church from any exaggeration or confusion between our Lord Jesus Christ and His blessed mother; no worship is offered to her, but only veneration and praise. In other words, in the Orthodox Church there is an accurate line that divides Lord Jesus Christ from His blessed mother; the only one who was Immaculately Conceived is our Lord Jesus Christ.

This lecture is adapted from ‘Comparative Theology’ by H.H. Pope Shenouda III and ‘St. Mary in the Orthodox Concept’ by Fr. Tadros Malaty.
http://www.suscopts.org/messages/lectures/marilecture1.pdf

[quote=Hieromonk Ambrose]St. Mary’s Immaculate Conception:

Some Church fathers do not believe Virgin Mary to be without faults, such as St. Irenaus, Origen, St. John Chrysostom. However, these opinions do not represent the widespread Mariological Tradition of the early Church.

We believe that St. Mary’s holiness is unique and surpasses heavenly creatures; she passed all her life in holiness as the true Ark of the Covenant, which was made of incorruptible wood laid with Gold from inside and outside.

The Orthodox Church, whose love towards St. Mary is deep-rooted, considers her more holy than all the heavenly creatures, whilst a natural member of the human race.

We do not set her apart from the human race by assuming that she was born without original sin (immaculate conception), as if she was born of no human seed. Thus, the Church makes a distinction between St. Mary’s life before and after the moment of Divine Incarnation.

St. Mary herself declared her need of salvation when she said, “my spirit has rejoiced in God my Savior.”
(Lk 1:47)

This Orthodox concept preserved our Church from any exaggeration or confusion between our Lord Jesus Christ and His blessed mother; no worship is offered to her, but only veneration and praise. In other words, in the Orthodox Church there is an accurate line that divides Lord Jesus Christ from His blessed mother; the only one who was Immaculately Conceived is our Lord Jesus Christ.

This lecture is adapted from ‘Comparative Theology’ by H.H. Pope Shenouda III and ‘St. Mary in the Orthodox Concept’ by Fr. Tadros Malaty.
http://www.suscopts.org/messages/lectures/marilecture1.pdf

The above repeats two errors. One, that the Immaculate Conception implies the Theotokos was conceived outside of normal intercourse between Joachima and Anne, which it does not. Two, that being restored to the original state that Adam and Eve enjoyed somehow seperates her humanity from ours, which it does not.