One point needs to be made before I launch into my larger explanation. One, we have to judge the principles, not based on the failure of persons to live up to them, i.e. liturgical abuse. I actually went to an Orthodox wedding a few months back that was just as bad as any bad Catholic Mass (and it was at the local Greek Orthodox Cathedral): it opened with a cheesy 70s style processional hymn, there was a pantsuited woman and two casually dressed men right up in front of the iconostasis that did the signing throughout the liturgy, there was no iconostasis doors, and the priest constantly broke with the flow of the liturgy to tell jokes or add his own stuff. I was actually excited to see this great liturgy and was thoroughly disappointed. But, it would be wrong for me to pass a judgment on the truth of their claims based on laxity amongst its members.
Next, as to yours and other posters claims about certain alledged corruptions that the Orthodox don't seem to practice or hold, this has only been true since their phase of exuberant anti-Latinism in the late 19th and early 20th centuries.
For example, a modern EO apologist will claim that we err with our understanding of original sin, when it was not an issue pre-schism and when they themselves taught the same understanding at the pan-Orthodox (ie their version of an ecumenical council without Rome)
Council of Jerusalem in 1672 (along with definitively numbering the sacraments at 7, using the word "transubstantiation," teaching the Catholic understanding of temporal punishment after death, mortal sins, the Catholic canon of Scripture, etc.). This pronouncement was used as a binding profession of faith for those who wished to be in communion with the Orthodox Church as late as 1721.
Similarly, they now call indulgences heretical when they issued them and even confirming their validity at the pan-Orthodox Council of Constantinople in 1727. Furthermore, the pan-Orthodox Council of Constantinople in 1838 condemned their use for enrichment--but not the practice, which continued until as late as the 1950s in the Greek Church. See here:
Indulgences in the history of the Greek Church / Ïðàâîñëàâèå.Ru (this article is translated by Bishop Tikhon of San Francisco and the West).
So either their Church was in error for centuries (and if so who knows what they're in error about now and have to get rid of later) or their Church dumped authentic Christian doctrines. Neither possibility is a good one.
Of course, they blow off these supposedly erroneous teachings of their own Church by saying that these Councils must be judged by all the faithful and they are only legitimate if they are accepted by the whole Church over an undefined period of time--which brings me to their main problem.
The main problem I see is the Orthodox do not have an externally veriafiable authority as part of their principles (although, historically they generally act contrary to their principles in this regard)--ultimately everyone must be individually led by the Holy Spirit--but how to discern the spirit of Truth from that of error?
Let's say there's some doctrinal dispute and I am confused as to the orthodox answer. So I await the judgment of the Church as to which side of the dispute is professing the true doctrine. A Council gets together and gives a definitive answer, anathemitizing all who disagree.
So, is this the authoritative answer? Not yet according to Orthodox doctrine, it must first be accepted by the whole Church. Who is the whole Church according to Orthodox doctrine? All orthodox believers. But who are the orthodox believers? The one's that believe the true doctrine. But what is the true doctrine?
With that last question we're back at square one. The Council was called to definitively settle the debate as to what the true doctrine is--but it must first be accepted by all those that already believe the true doctrine. But since I don't know the true doctrine, I can't tell if the people doing the accepting are the group I should look to. What about those that don't accept it? How do I know they aren't the ones who are right?
It seems historically this principle of requiring universal acceptance was not adhered to. A lot of people didn't accept the definitions of Ephesus and Chalcedon. Was their lack of acceptance taken into account? Nope, they were excommunicated forthwith. Obviously there will be universal acceptance when you kick out anyone who doesn't accept it!
It seems this theory was only practiced to reject the reunion Councils of Lyons and Florence (where the Orthodox accepted papal primacy, the orthodoxy of our use of the Filioque, etc.) and certain things taught in the pan-Orthodox Councils I mentioned above.
The point is that there is no way to determine whose judgment is right--those that accept the Council or those that don't?--other than for each individual to figure out every issue on his own. But that defeats the whole purpose of the decision of the Council which was convened to judge the issue for all of us and threatened us with anathema if we didn't receive its decision.
There must be a fixed and externally verifiable authority for this system to make coherent sense. That fixed (like a rock) authority has always been the Apostolic See of Rome.
Again, all of the problems in the Catholic Church are from people not living up to our principles. The Orthodox problem is in their principles.