Papal Infallibility is a true dogamtic difference.
I think Papal Infallibility is truly a dogmatic difference, but it isn't the only one. It isn't the only Roman Catholic Dogma that the Orthodox Church regects.
Papal Primacy is not so much
the issue as the way it is exercised.
I am talking about Papal supremacy here. I do not think Orthodoxy denies Papal Primacy. The Pope, according to Orthodoxy, is the first amoung equals, therefore holds a primacy of honour. However, Catholicism gives the Pope supremacy, total jurisdiction over the entire Church, a primacy of jurisdiction one might say, that rapidly grew into a supremacy in the 12th and 13th centuries. So here we have a serious difference, that turns into a dogmatic one with the declarations of Vatican I.
The rest I feel can be worked out and are being worked. Only hardliners on both sides insist they constitute insurmountable differences of dogma.
It is sad, and in a way, funny, that those on both sides who adhere to the basic teachings of their Churches are considered hardliners. Catholicism and Orthodoxy both claim they are the true Church, and the other is in schism. There is no room for compromise here. I am sorry, but this is the truth. When you have two Churches, both claiming to be the true Church, you can't have compormise, one must repent and unite with the other, or there really can't be true union, without the West giving up on some of it's dogmas, and the East embracing some of the dogmas they've regected for centuries.
No matter what Vatican II may have said, or what those who desire union above anything else may say, it is still offical Catholic teaching and dogma, that Catholicism is the truth, and there is no salvation outside of the Catholic Church. But if I, as a Catholic, go around saying "Catholicism is the truth, all else is heresy, repent, for there is no salvation outside of the Catholic Church!" I would be labled as a hardliner and a nut, even though such a statment would be a simple expression of official Catholic teaching.
For example, the Spanish Church had been reciting the Filioque long before the Schism yet the East did not feel it was an issue worthy of schism until after the Photian/1054 schisms.
This is a good point but the problem now is that the Filioque is offical Catholic dogma. For the RCC to give up the filioque, it would have to admitt it is not the true Church, for the Catholic Church declared the filioque a dogma. There has been no rejection of this dogma and the anathema against those who don't believe in the filioque has never been refuted by Rome. You can't work around this. The Catholic Church holds the Filioque as a dogma, nessicary for salavation, but the East totally rejects it. So we have a problem here, for either side to compromise would be unthinkable, for both sides officialy teach they are the true Church, and the other is in schism/heresy.