The Orthodox often forget the importance of the Magisterium for Catholics.
1. The Orthodox receive their faith through the transmission of the sacred Tradition which takes a variety of forms. Bishops, priests and laity alike are all guardians of the Tradition and must be obedient to it.
2. Catholics on the other hand are expected to be submissive to the Magisterium and to its official Magisterial teachings. Whatever of their tradition has not been codified into a Magisterial teaching is really nothing more than what the Orthodox might call theologoumena-opinion. Up until the Bull Munificentissimus Deus Catholics were quite entitled to deny that Mary the Mother of God was assumed into heaven, just as they had been able to deny she was immaculately conceived. Ditto for the Pope's infallibility - until 1870 nobody really knew if he were infallible or not.
I have learnt this major difference between our Churches in the way we approach the faith the hard way. I instinctively fall into the error of thinking that Catholics are subject to Tradition and I have often written of their traditional beliefs as if they are a certain part of their faith. In the absence of a magisterial teaching they are not. They are only an interim belief/opinion on which you cannot place much reliance.
I think I have written about this here previously? Teachings which have been taught and believed for centuries as part of Tradition within Catholicism may be annulled and superseded by subsequent teachings and definitions.
There actually is a great gulf between our Churches on this matter. The certainty of our faith is grounded in our Tradition,. The certainty of the Roman Catholic faith is grounded in magisterial statements. In other words, the faith is effectively taken out of the hands of the Church as a whole. The faithful are disenfranchised and the faith is posited in the hands of a small elite group known as "the Magisterium." I frankly would not wish to be in communion with a Church which has this disjunct between its upper echelon and the great majority of its members.
Let me say first that you make a number of good points there.
I believe however that you are mistaken on some nuances. Consider, for example, the question of how many Marian dogmas there are in Catholicism. Many Catholics assert (rather dogmatically!) that there are neither more nor less than 4, but many other Catholics find that position quite illogical. See, for example, the treatment in
Not Fifth, Not Final, Not Yet A Dogma
However, the claim that there are only four dogmas (with the proposed dogma counting as fifth) is based on a very narrow definition of what constitutes a Dogma. Dr. Mark Miravalle asserts in quote 5 above that a teaching is not a dogma, even if it has been infallibly taught by the Universal Magisterium, unless it has been solemnly defined under Papal Infallibility or by an Ecumenical Council. But there are a number of problems with this restrictive definition of the term 'dogma.'
First, the Marian dogma which teaches that Mary is ever-virgin, in other words, that her virginity is perpetual, was never defined under Papal Infallibility, nor by an Ecumenical Council. There is no solemn definition which specifically and infallibly teaches that Mary is ever-virgin. Now this teaching is certainly a teaching of the infallible ordinary and universal Magisterium, and so the doctrine itself is indisputable. But under the narrow definition of the term dogma used by supporters of the Vox Populi position, there would only be three current Marian dogmas, and their proposed dogma would be fourth, not fifth.