Not really. No, I would not agree. I think it is important to discuss these previous RC encyclicals and teachings and see how they compare with the post Vatican II teachings and further how they would fit in with the RC EO dialog. After all, according to RC belief, teachings never change essentially, isn't it true?
The question of doctrinal continuity is an interesting question, but it is not what is being addressed here and probably cannot be addressed here, because the Catholic understanding of magisterial authority and the hermeneutics of dogmatic statements is not easily grasped by non-Catholics--heck, it's not easily grasped by Catholics. Catholics vigorously debate among themselves the continuity of specific magisterial teachings--usury and religious freedom immediately come to mind.
What is at issue here in this thread is the impropriety and arrogance of someone outside the Catholic Church telling Catholics what their dogmas mean. Just as it would be improper for a Catholic, Lutheran, or Baptist to tell the Orthodox what their Church authoritatively teaches, so it is improper for Orthodox to tell Catholics what their Church authoritatively teaches. Churches are living communities and their beliefs cannot be reduced to dead formulae. The members of a given community are the best, and indeed only, interpreters of the beliefs of that community.
I can understand how a non-Catholic might say to a Catholic, "On the basis of the Baltimore Catechism, Catholics appear to believe that purgatory is a place where people must first be punished by God before they are admitted into his presence" (or something like that). But if the Catholic replies, "No, that is now what we believe. We believe ____," then the non-Catholic should accept, if only out of politeness and charity, the Catholic's interpretation of his Church's teaching. Of course, it might well be the case that regarding the doctrinal question being discussed Catholics might disagree among themselves, and such disagreement may and should be noted; however, the non-Catholic has no right to enter into the inter-Catholic debate and take sides, as it were. The only folk who are competent to tell non-Catholics what Catholics believe are Catholics themselves.
If we assume that both parties in a conversation are committed to truth and mutual understanding, then it seems to me that both parties will go out of their way to ensure that they are not misrepresenting, distorting, and caricaturing the views of the other. Otherwise, what's the point of the conversation?