No, no and no.
Let's step back for a few moments and think this through: [sorry I'm longwinded. I want to give precise answers]
1. the Catholic Church is not a religous sect led by a guy in Rome. It is the sheepfold of the God, who created heaven and earth; founded by Him and guided by His Spirit, given to the care and leadership of twelve people who were consecrated as His ministers, and under the leadership of St. Peter. EVERYONE who has been baptized, chrismated, and permitted to receive our God's body and blood, from a
legitimate "descendant" of an apostle who holds the orthodox faith , and whether he's Latin, Byzantine, Coptic, Assyrian, or whatever, is a member of the Catholic Church. This is also true regardless of whether this community, led by a particular bishop, is in union with any other particular bishop. So, all [big O]
"Orthodox" are part of the Catholic Church by virtue of their apostolic succession and their adherence to the orthodox faith, regardless of whether or not they're in union with Rome.
Dominus Iesus, par. 17 [
vatican.va]
2. Now, most of the Patriarchates and Eparchies who are descended from the tradition of Constantinople are not in union with Rome. This is because these churches believe that the insertion "filioque" in to the Nicene Creed, the Augustinian definition of orginal sin, and the current understanding of the role of the Pope of Rome in relation to the rest of the Church, are
denials of the "deposit of faith" given by Christ to His Apostles . Of course, a better understanding on both sides is mitigating this, but nevertheless we're far from smoothing them over and for now the schism formally exists.
3. However, some Patriarchates (including parts of the great Patriarchates of Antioch and Kyiv) and Eparchies returned to Rome unilaterally for various reasons, enduring the censure of the remainder of those Patriachates and Eparchies. Of course, there have been Latinizations and things like that, a result of the culture of the west's belief that it was superior to that of Byzantium. Some of those Patriarchates and Eparchies went along with this, influenced by a theological (for lack of a better word) process alien to their religious culture and probably in order to "fit in". But thankfully that era is essentially over and our Churches can - and MUST - keep a religious culture like the rest of our tradition.
Your question is, in my mind, like asking "should these Churches - who rejoined Rome - say that Rome is in heresy, in order to facilitate the reunion of the remaining Churches of their tradition"? I don't think there's any reason to do so, and I don't think that it would help reunion.
I would never go with it either. I do believe that to become Orthodox you have to essentially assent to the idea that the whole communion of Churches under Rome are more or less in heresy. I cannot bring myself to seperate from the Archdiocese of Santa Fe, or the Diocese of Arlington, through whom God has provided my so many gifts - including baptism, the gift of the Holy Spirit, and the gift of the Eucharist. I cannot bring myself to essentially declare invalid St. Anthony of Padua and St. Thomas Aquinas, whose prayers have been plentiful and essential to me. I cannot declare that the great men John Paul II and Bendict XVI, though great Church leaders, cannot currently be in union with my Church because of profound questions about their full adherence to the orthodox faith.
As usual, if anything I've written regarding truths of the Catholic faith is wrong, I will immediately retract them if corrected by a clergyman or someone with a better understanding of the issue than I.
