One of the things I've taken to doing recently is going to Mass (I generally attend a Novus Ordo Mass, even though I prefer the TLM) with my traditional Sunday missal. During the Mass, especially starting right after the Credo, I follow my missal instead of whatever is going on in the local Mass. I believe the form of the traditional Mass (especially the prayers of the Offertory and the Canon) better express the essence of the Mass than does the form used for the Novus Order. Accordingly, by focusing on those traditional prayers, I believe I more actively participate in the Mass going on in front of me, than if I were to join the congregation around me in the modern forms.
But that's not what this is about.
As part of following a traditional Sunday missal, I've noticed something about the liturgical calendar as it existed prior to the post-Vatican II reforms: The entire year is expressed in terms of the chief events and feasts of the Church.
The liturgical year starts with Advent, which leads into Christmas. This is the same as the modern calendar. But then Christmastide is capped with the celebration of the Epiphany. From that point on, all the Sundays up to Septuagesmia Sunday are named according to their relation to Epiphany: First Sunday after Epiphany, Second Sunday after Epiphany, etc. Septuagesima Sunday is named for its relation to another feast: It is seventy days before Easter. The next Sunday, Sexagesima Sunday, is (about) sixty days before Easter, and then Quinquagesima Sunday is (you might have guessed) about fifty days before Easter. After Quinquagesima Sunday comes Ash Wednesday, which starts the penitential season of Lent, which leads to and is meant for preparation for Easter. Easter Sunday starts the season of Easter, commonly called "Paschaltide." Paschaltide extends to the Pentecost, and ends in a ten-day stretch called Ascensiontide, which is the time from the Feast of the Ascension to the Pentecost. For the remainder of the year, the Sundays are (generally) named for their relation to Pentecost.
This system does a wonder work of keeping one grounded in liturgical time. Every Sunday (more frequently, if one prays the traditional Divine Office), one is kept aware of the most relevant significant feast for the time of year, and reminded that the life of the Church is all about the events celebrated by these feasts - especially Pentecost.
So, what about the modern calendar? As a matter of first impression, if one needed to come up with a liturgical calendar and were given the general structure and priority of feasts, one could do worse than the modern calendar and its use of Ordinary Time. But it doesn't come close to accomplishing what the traditional calendar does, in terms of rooting the liturgical life of the individual Catholic in the spiritual life of the Church.
The problem is that we're not in a situation of first impression. We had an existing calendar that had been arrived at with some centuries of wisdom. Then somebody decided that the spiritually edifying aspects of that calendar needed, for some reason, to be gutted.