What does it mean that the "patriarch isn't the Church?" Is the Pope the Church?
As for Constantinople seating heretics, this is because the East became a hotbead of theological development and debate, and not just Constantinople - Alexandria and Antioch as well.
Rome became thelogically dormant by comparison in those years and the pope/bishop of Rome reduced to little more than an ecclesiastical referree of sorts.
The Protestant Reformation didn't disagree on what the popes taught. They reacted to perceived deformations of Christian teaching and practice - albeit going in the wrong direction in opposing them.
Also, the trend in discussions of this sort seems to go toward a soft-sell of papal triumphalism.
In what way is the Oriental Orthodox family of Churches deficient by way of: 1) Apostolic Faith; 2) Sacramental Validity and 3) Ecclesial Authority?
They are not in union with the Papacy. But is the Papacy in union with the Roman Primacy of the first thousand years?
Asking, not telling.
Alex