My grievous concerns about Eastern Orthodoxy are:
1. She does not share our understanding of original sin. I am not saying that she is Pelagian, just that she has a deficient understanding of the sinfulness of man.
2. She does not share our understanding of substitutionary blood atonement.
In my discussions with the EO in Israel, and in particular the Russian Orthodox, I came to understand that they view the sinfulness of man and his native estrangement from God to be based upon ignorance, and thereby an implicit vestige and capacity for goodness and righteousness, rather than the legal/covenantal concept that we developed in the West (and what is clearly taught in scripture- in Adam,
all are covenantally bound to sin, rebellion, and eternal punishment save those who are joined to Christ's covenant). The notion of an inherent goodness to man is at least semi-pelagian in nature- to say that the Orthodox have a "deficient understanding" is a bit of an understatement.
Lacking a legal/covenantal understanding for anthropology, and when challenged with clear passages about man's native inability to be righteous before God, the Orthodox tend towards throwing their hands in the air and saying "It's a mystery!" That the EO would fall back upon the
mystery of doctrines rather than rely upon what is clearly stated in the text of scripture, and that they reject substitutionary blood atonement, is to further drive the point.