Some readers might be aware of a Russian, and to some extent, Romanian, Orthodox group called the "Old Believers." Their's is a fascinating case study in liturgical upheaval's most extreme consequences. The Patriarch of Moscow in the mid-17th century, Nikon, noticed differences between the Greek and Russian Church liturgies in some very basic matters: the direction of a procession, how to say the Creed, how to make the sign of the Cross, and even Our Lord's Holy Name. Nikon, in a bout of wisdom from Solomon, assumed that whatever was Greek must be older and hence more authentic. He imposed many major liturgical changes (so much for those who think the Byzantine rite is super ancient and un-altered) and, with the help of an Orthodox synod in the 1660s, even anathematized the older Byzantine liturgical practices with the czar's approbation. Many who refused the changes, the "Old Believers," suffered violent consequences, including Feodosia Morozova, whom they esteem as a sort of martyr for her death-by-starvation in a jail cell. The resulting schism endures to this day.
Many Old Believers have dispersed throughout Eastern Europe in small droves and even into Alaska, where one community frequently attracts the attention of the press, which sees the Old Believers as a quaint, Amish-like group of benign persons. Most tragic about the Old Believers is that they were probably more in the right than Nikon was, who just assumed whatever was Greek must be better. I do not know much about mid-second millennium Byzantine liturgy, but as a former student of medieval history I can say that as a center of trade and the delta of several currents of ideas from Latin Europe, Arab North Africa, the Holy Land, and the former Greek Empire, the Constantinopolitan liturgy would be especially susceptible to alterations and changes. Moreover, the wealth of Byzantium, until its fall in 1453, meant both institutions and individuals could afford the creation or copy of books, fostering many opportunities for typographical errors and the machinations or copyists. Russia, as a poorer and geographically desolate place, would be better suited for the preservation of written and oral liturgical traditions.
This should be a lesson to those who wish for immediate liturgical changes. Even enthusiasts for the old rite ought to realize that an outright and instantaneous change in the Latin rite would do more harm than good.