I was listening to one of Dan Carlin's podcasts about the Anabaptists in Munster and this struck me. Was there less corruption in the Eastern Church? Stronger central government would preclude some of the problems but the Russians, etc at that time were plenty fragmented, right? Just curious.
If you ask a orthodox christian why they are orthodox instead of catholic, they will say it is because the orthodox church is the original Church that has never changed since its formation in the 1st century AD. The last christian council recognized by the orthodox church was the ecumenical council of 787 AD and since then there has been no theological changes in the orthodox church. Everything is exactly the same: the liturgy(mass) said every sunday in orthodox churches around the world is usually the Divine Liturgy of St. John Chrysostomos(written in the 5th century) and sometimes the Divine Liturgy of St. Basil the Great(from the 4th century). The style of the robes worn by the clergy has not changed in over 1000 years. There are even some orthodox churches who never changed to the Gregorian calendar, which was adopted by most of the western world in 1582. Yes, there have been some periods of temporary change such as the iconoclasm periods(destruction of icons) that is similar to some protestant reformations but these movements were instigated by governments, not the church.
Compare this to the catholic church where in addition to the first 7 councils, there have been an additional 14 councils, the most recent being the 2nd Vatican Council in the 1960s. The purpose of the original 7 councils was to clarify specific points of faith for the new christian religion. However, for the catholic church, this willingness to continue to have councils speaks to the concept that a church should be periodically updated to match a changing world, instead of the people of the world changing to match the church. This concept is the antithesis to the orthodox church because the church believes that it's greatest strength is its unchanging nature. Thus, there will probably never will be any serious reform movements in the orthodox church.
This is actually a difficult question to answer, because you're asking "Why didn't X happen?" which is counter-factual history. In short, the answer is because the conditions that obtained in reformation Europe against the background of western Catholicism never occurred in Eastern Orthodoxy.
I suppose, to rephrase, one might ask, "What are the factors that have hampered or suppressed significant reforms in the Orthodox church?"