When the west under the political influence of the Franks began demanding that the Orthodox add the filioque to the Creed (and actually accusing them of having omitted it from the original Niceno-Constantinopolitan creed) I agree that the east had every right to feel insulted and be upset. I don't think they should be forced to say it in their creed.
It may be the case that the Orthodox will be willing to omit it from their creed while not holding to the view that its inclusion is in principle heretical. But that isn't the same as the giving up of dogmas, which is what I was addressing. As regards the Immaculate Conception, likewise, if the Orthodox consider it to be heretical because they consider the doctrine of Original Sin (contra Ancestral Sin) to be heretical, there won't be a substantive union.
When there is substantive agreement on what the west has taught about original sin, and when the east stops asserting that the Catholic Church teaches a personal form of original guilt, which is where we are with it now, then the doors open for many understandings.
As I said it is not just a matter of acceptance but how one accepts a doctrine. Again it has already been said and understood that the east will not be asked to accept more than what was accepted up until the schism, in the same manner as the west has been asked to accept it.
What will be asked is that the east cease calling western teaching heresies, and that the west stop looking upon the east as something lesser in her faith.
These things are what will provide grounds for resumption of communion. What we do from there?...only the Holy Spirit knows...
If you have not read it, I suggest that you pick up and read Joseph Ratzinger's Principles of Catholic Theology. He is not just speaking of the Catholic west when he writes about theology. He is too deeply read in the Holy Fathers to speak only of the west when he speaks of our shared theology.