I've also been mucking about in various Orthodox Church sites. Much of what I see feels good. I like the idea that the basis for Christian union is to return to the undivided faith of the First Millennium.
My problem with the Eastern Orthodox Churches is the same as my problem with the Roman Catholic Church: ecclesiology. The Old Catholics probably come closest to an understanding I could live with as a basis for unity. But the whole idea, "you can come back whenever you want to" I find presumptuous.
I cannot speak for all Protestants, or even for all Methodists, but as a child of Wesley I see what I believe to be the Hand of God in our origins. We did not leave anybody, so much as we had to solve certain problems presented to us by our frontier conditions -- and by the unwillingness of our elder sister Churches to fulfill the Gospel mandate. As a UM Superintendent in Kansas said, regarding the independent churches springing up everywhere nowadays, "These are the stones crying out." Because we would NOT raise up a witness, God has raised up for himself those who will praise his Name. In our day, 200+ years ago, we were "the stones crying out."
A full reconciliation among all the major branches of Christianity ought to be based, first of all, on the faith of the undivided Church of a thousand years ago; and second, on a recognition that the controverted problems of primacy, order, organization, and sacraments cannot be solved while ignoring a thousand years of complicated history.