Part of the split between East and West concerns a divergence in Church culture. Some of this can be traced back to the very earliest times, some from the Fifth Century, some from after the Eighth Century but most from after the Eleventh Century. This culture is a matter of how things are done in practice, from things such as Baptism to shaving. Some of the issues are canonical where in some cases the West/East did not know/receive those canons held by the other and sometimes, when it did, they were sometimes ignored/changed such as kneeling on Sundays. A number of issues can be traced back to the Apostolic Constitutions, which, although not regarded as binding, had a strong influence on what, in the East, was understood as Tradition. Somehow this influence seems to have been missing in the West, although historical research, at least in the secondary non-polemic literature I have read, does suggest that in the early centuries there was a much closer culture between East and West in many of these areas such as fasting and Baptism, which reflect the Tradition as seen in the Apostolic Consistutions.
Many regard practice as secondary or incidental to faith and because it is physical action, it is changeable. However, this does not seem to be the mind of the Fathers, who regard the practice of the Church, Tradition(s), as unchangeable as the Faith, with some exceptions. This is, I understand, because the unchanging Son of God became incarnate and took matter to participate in His unchanging life. The practice of Tradition reflects this unchanging life, which is truly incarnate not just a spiritual or conceptual reality. Thus, we would expect to see this life manifest in a physical and practical manner. Matter and action also play a part in salvation because both soul and body are saved not just the soul; we are judged for the deeds done in the body. When Christ was incarnate He took on a particular form, which remains His eternally, hence the ability to paint icons of Him. Being incarnate means limiting oneself to a particular form. The amazement of the Angels in seeing Him beyond form who fills the heavens, i.e. is omnipresent, coming to earth, i.e. into time and space, with a particular form. This though did not prevent Him maintaining the fullness of His divinity. Thus, the rites/practices of the Church can take on particular forms that continue to incarnate the mystical presence of Christ and these forms take on a permanence due to their connection with Christ.
So, when the culture/practice of life changes there is a sense that somehow the faith is changed with this and the new practices no longer reflect the presence of the incarnate Christ. However, not always, as some of the schisms in the East, such as that of the Old Believers, have shown. Nevertheless, these schisms do highlight the Orthodox mind, even if taken too far or simplistically (not all Church rites/practices are necessarily single formed and different forms can portray various aspects of the same mystery), where there is a strong connection between faith and practice.
The change of culture has played an important role in the separation and continuance of separation between East and West, at least the evidence of Eastern concerns about these matters show they were concerned about it to the level of anathemas for “false” rites/practices. Any reunion must not only see an agreement of matters of Faith, i.e. the filioque, and jurisdiction, i.e. the Papacy, but also on matters of practice such as Baptism, the bread for the Eucharist, kneeling, music, icons, fasting, marriage and others. Some different practices maybe be accepted as legitimate and acceptable by both sides, some may be overlooked because the change would be too difficult to implement overnight, but others maybe such that cannot be put aside; there must be a common practice with agreed limits on economy in necessity. Obviously the Ecumenical Councils have already defined much of this and what is often needed is a return to that practice.
Nevertheless, I believe that there is no point discussing practical things in depth until matters of Faith and mindset are sorted out. Once there is a common mind then matters of dispute can be discussed within the same way of thinking. Otherwise, we will just talk past one another to no benefit. These practices must still be addressed before union is possible but in the proper order. Having said that, it can be useful to consider the culture/practices of each other because it does help to get a better idea of each others way of thinking as long as we do not try to interpret it entirely from our own perspective; it is learning to alter perspective that is the point of the consideration.