The new calendar practically omitted the vigils (including the one at Christmas); all that remained was a Mass on the evening before (which lost its importance as a result of the anticipated festal Mass). The number of vigils was perhaps too high, but I do not believe that a purging preparation for greater solemnities is necessarily obsolete. The octaves with the repetition of the solemn Mass might also have been too frequent. The calendar left only two octaves untouched (in practice only one, that of Easter). The true meaning of the octave is not, however, to repeat the liturgy of the day, but to give more time to assimilate the content of the feast: this meaning could have been preserved by liturgical means.
In my opinion, one great failure of the reform was the shift of the solemnity of Epiphany and Ascension to Sunday (ad libitum). It was with good reason that the dates of these two feasts were fixed: the first was decided by a very old and universal (also ecumenical) tradition, the second by the decision and deed of the Lord himself By being moved, they became simply the “theme” of two Sundays, and caused confusions in the calendar. Was it not too big a concession to secularism to allow the date of two great solemnities to be set according to the position of civil holidays? Is it too much to expect from the faithful, from those “initiated in the Paschale Mysterium,” from those “living in Christ,” those “devoted to God,” to attend Mass twice in a year after their day’s work (knowing that if they are unable to do so, they are automatically exempted from this obligation anyway)? Is it right that Catholics in different countries celebrate these great festivals on different days?
Laszlo Dobszay, The Bugnini-Liturgy and the Reform of the Reform (2003)