The issue of Denominational Christianity is a misnomer and not a part of Orthodox tradition. In fact, the Holy Orthodox Church is not a 'denomination' of Christianity. The Holy Orthodox Church is One, Holy, Catholic, and Apostolic. The Holy Orthodox Church knows no divisions or discord within its ranks. As happens to any vine, certain of its branches become diseased and fall away as chaff. Likewise, in the history of the Holy Orthodox Church there has been a series of 'branches' that have have fallen from the vine of Christology. When such happens, the branch ceases to be in communion with the rest of the Body. The situation with the various 'schisms' are, in fact, treated (properly speaking) as diseased branches of the Body (in danger of extinction) which no longer receive proper nourishment by the action of their doctrines, innovatively foreign to the Gospels and Tradition of the Faith, expressed by the Holy Spirit in concert with the Seven Holy Ecumenical Councils.
The problem with modern day 'Christianity' is that of attempting to express the Unified Faith of the Gospel of Christ in the context of several elements, foreign to its concepts. For example:
1. the belief that Mary is merely the Mother of Jesus, without more. 2. the belief that Mary had other children after Jesus with her husband, Joseph. 3. the belief that Jesus is not Divine, but just a good teacher. 4. the belief that Jesus is Divine, but not human...perhaps an alien being from outer space. 5. the belief that Jesus teaches mysticism and good works, being a good Rabbi, without more. 6. the belief that Jesus is a stream of consciousness, or a level of thought, ala Zen Buddhism. 7. the belief that Mary Magdalene was a prostitute. 8. the belief that the accounts of miracles in the Gospels should be somehow watered down. 9. the belief that certain accounts in the Holy Scriptures are mythological. 10. etc.
Thus, Satan preaches another gospel of humanistic origins that is designed to cause contentions in the Faith, by stealth and guile. However, there are not many gospels, but One Gospel. As such is the case, Orthodox Christians should be diligent to defend the One, Holy, Catholic, and Apostolic Faith of Christ Jesus. 'Denominationalism' is a product of Satan's attempt to confuse those who would adopt the Christian Faith. Such is the result of power, pride, jealousy, hatred, fornication, and lust. In history, the Church has been made whole by the power of the Holy Spirit through the Holy Apostles by the leadership of Jesus Christ through God the Father (the Source of Godhead is God the Father). The Romans have been the principal sovereign power over Earth's Kingdoms, since the time before our Lord was presented to the world in Bethlehem. 2007 years ago. The influence of the Roman Empire permeated the Patriarchate of Rome in 800 A.D. and caused the Great Schism of 1054, ultimately. The 'Roman Catholic Church' became scholasticized, manipulated, and worldly after the fashion of pagan Romanism. The centralization of power within that Roman religious institution is evidence of the agenda of the Empire's designs over its life and 'faith'. More so, the superstitiousness of its peoples, is further evidence that the Roman Empire wished to control its people through its State religion.
It is not surprising, therefore, that the Reformation movement which sparked the first 'protestant' 'churches' was, in a real sense, a product of the poison fruits of heresy. Ironic it is to see the 'protestant churches' following the leadership of men and women, instead of following the Head of our Ecclesia, Jesus Christ, our Lord and Saviour. It is all the more ironic that these leaders were considered infallible foundations in matters of Faith and Dogma. The seeds of discord and contentions were planted in such 'protestant churches' by not resolving such differences in any collegial councils, by not recognizing the authority of the Holy Spirit. This foregoing problem of contentiousness and division has only gotten worse to the tune of 300+ denominations of totally distinct 'theologies', and foreign to the Faith and Life deposited by Holy Scripture and Holy Tradition in accordance with the Seven Ecumenical Councils.
How is it best for Christian Orthodoxy to resolve this problem? Such is probably addressed through Evangelism, the open discussion of the meaning of the Holy Canons of the Orthodox Church, and the invitation to bring these peoples into the Saving Knowledge of the Unified Faith, which is not foreign to us (or to the Gospel of Christ). It is definitely against Holy Tradition and Holy Scripture for us to entertain dialogues with the Pope of Rome, without full explanation of the things that Holy Orthodoxy requires of the Romans to dispel the heresy that they inflicted upon the Body of Christ. It is also incumbent upon us as Orthodox Christians to educate the 'protestants' in the Unified Faith of Christ Jesus in a manner that is constructive and Faith building.