Taft's big mistake, I suspect, is to fetichise Councils and, by expecting too much of them, to have problems when they fail to live up to the standards he has set them. This is not surprising; given a lifetime of scholarly work on Byzantine Christianity, it is natural that he should have some of its unspoken assumptions rubbed off, as it were, upon him. And an extremely high regard, even an adulation, of councils, seems, to the poor and ignorant Westerner who is writing this, to be a marked feature of Orthodoxy (I am humbly open to correction from Orthodox readers). I have two reasons for wishing to enter qualifications.
(1) I believe such an attitude gives all councils a status which is exaggerated.
(2)* I believe it leaves insufficiently regarded some councils which were not formally 'ecumenical'; and undervalues the profound significance of the Magisterium of the Roman Church.
(1) I believe that it is not only 'post-schism' councils which Joseph Ratzinger had in mind when he wrote Not every valid council in the history of the Church has been a fruitful one; in the last analysis many of them have been just a waste of time. And I would add that sometimes they have been corrupt, venal, and violent; sometimes they have been open to excessive influence by secular influences, whether of Roman or Byzantine Emperors, or of French kings. Sometimes, in the words Newman angrily used of Vatican I, they have been dominated by an aggressive insolent faction. And some even of the Great First Seven Councils were sparsely attended and unrepresentative of the Oikoumene. Just as we are not required to like the Sovereign Pontiff or to approve of his obiter dicta et obiter acta, though we are required to be humbly and completely subject to his authentic Magisterium, so we are not required to admire the proceedings and the participants of Ecumenical Councils but simply to accept their dogmatic Magisterium. I have said before that I dislike the absurd personality cult which surrounds a modern pope. I dislike equally an uncritical and historically uninformed enthusiasm for councils.
Furthermore, as I have argued previously, those conciliar enactments which are not definitions of dogma definitive tenendum are marked with an implicit sell-by date. Addressed to the circumstances of a particular era, they are less relevant when that era has disappeared ... they pass, as I believe I once wrote, into the general background noise of the Church. Our decade is so profoundly different to the 1310s and the 1960s that I believe we have reached this stage with regard to the Councils of Vienne and of Vatican II (but not, in as far as they defined, with attached anathemas, authentic Catholic dogma, with regard to Chalcedon, Trent, or Vatican I).
But I would regard as just and appropriate the censuring of a writer who called into question whether either Vienne or Vatican II was a fully authentic (in Ratzinger's word, 'valid') Ecumenical Council of the Catholic Church.
That is why I would like to see Robert Taft censured, while being quite sure that there is no need to censure Joseph Ratzinger.
*(2) will, DV, follow later.