So, under such a hypothetical what would it be - assume that in the hypothetical a Pope has redefined or reinterpreted Pastor Aeternus in a manner acceptable to the Orthodox?
Oh why not be wild and crazy and "read" Pastor Aeternus as it was intended by the moderates and see what you get?....Don't even have to change the durned thing. Just read it as it was intended and as it was further refined during the Second Vatican Council...
Nah....can't do that...
Words do have meanings. Since the Catholic church invented much of what has become our Anglo-American system of jurisprudence and in particular, the venerable rules to be applied to the meaning of words and phrases in a contract, it is important to view the actual words of Vatican 1. It is fair to consider documents such as Pastor Aeternus as being in the nature of a contract between the Church and her faithful so...
Quoting directly from the aforesaid document, I fail to see how understanding a 'moderate' view can temper what it says? (I have the same problem with constitutional law and 'original intent' vs. 'the living document' as well as with court's of law determining 'legislative intent' by the way...but that is a whole 'nother debate....)
From Pastor Aeternus and thanks to EWTN for posting it : http://www.ewtn.com/faith/teachings/papae1.htm"Chapter 2: On the permanence of the primacy of blessed Peter in the Roman pontiffs:
....3. Therefore whoever succeeds to the chair of Peter obtains by the institution of Christ himself, the primacy of Peter over the whole Church. "So what the truth has ordained stands firm, and blessed Peter perseveres in the rock-like strength he was granted, and does not abandon that guidance of the Church which he once received" .
4. For this reason it has always been necessary "for every Church--that is to say the faithful throughout the world--to be in agreement with [the Roman Church] because of its pre-eminent authority."....Chapter 3: On the power and character of the primacy of the Roman Pontiff
1. And so, supported by the clear witness of Holy Scripture, and adhering to the manifest and explicit decrees both of our predecessors the Roman Pontiffs and of general councils, we promulgate anew the definition of the ecumenical Council of Florence , which must be believed by all faithful Christians, namely that the "holy Apostolic See and the Roman Pontiff hold a world-wide primacy, and that the Roman Pontiff is the successor of blessed Peter, the prince of the apostles, true vicar of Christ, head of the whole Church and father and teacher of all Christian people. To him, in blessed Peter, full power has been given by our lord Jesus Christ to tend, rule and govern the universal Church. All this is to be found in the acts of the ecumenical councils and the sacred canons."
2. Wherefore we teach and declare that, by divine ordinance, the Roman Church possesses a pre-eminence of ordinary power over every other Church, and that this jurisdictional power of the Roman Pontiff is both episcopal and immediate. Both clergy and faithful, of whatever rite and dignity, both singly and collectively, are bound to submit to this power by the duty of hierarchical subordination and true obedience, and this not only in matters concerning faith and morals, but also in those which regard the discipline and government of the Church throughout the world.
....4. This is the teaching of the Catholic truth, and no one can depart from it without endangering his faith and salvation.
8. Since the Roman Pontiff, by the divine right of the apostolic primacy, governs the whole Church, we likewise teach and declare that he is the supreme judge of the faithful  , and that in all cases which fall under ecclesiastical jurisdiction recourse may be had to his judgment  . The sentence of the Apostolic See (than which there is no higher authority) is not subject to revision by anyone, nor may anyone lawfully pass judgment thereupon. And so they stray from the genuine path of truth who maintain that it is lawful to appeal from the judgments of the Roman pontiffs to an ecumenical council as if this were an authority superior to the Roman Pontiff.Chapter 4: On the infallible teaching authority of the Roman Pontiff
9. Therefore, faithfully adhering to the tradition received from the beginning of the christian faith, to the glory of God our savior, for the exaltation of the Catholic religion and for the salvation of the christian people, with the approval of the Sacred Council, we teach and define as a divinely revealed dogma that when the Roman Pontiff speaks EX CATHEDRA, that is, when, in the exercise of his office as shepherd and teacher of all Christians, in virtue of his supreme apostolic authority, he defines a doctrine concerning faith or morals to be held by the whole Church, he possesses, by the divine assistance promised to him in blessed Peter, that infallibility which the divine Redeemer willed his Church to enjoy in defining doctrine concerning faith or morals. Therefore, such definitions of the Roman Pontiff are of themselves, and not by the consent of the Church, irreformable.
If they didn't mean to say what this clearly says, they shouldn't have said it at all. I rest my case - I still can not understand how my Eastern Catholic brothers and sisters can accept those definitions. (I am sure that an educated canonist like Fr. Alexis Toth, i.e. St. Alexis of Wilkes-Barre, must have been well aware of this document at the time of his meeting with Archbishop Ireland.)
As I have said repeatedly, there is no logical wriggle room here and to agree to disagree is the best we can accomplish since Vatican 1 so clearly defined the papal prerogatives.