GIRM 29-45 addresses “Different Elements of the Mass.” In these sections, we’ll look at the readings, prayers, other texts, speech style, singing, gestures, posture, and silence–all the important qualities of liturgy that apply to the various aspects of celebration.
Today, the importance of the Word:
29. When the Sacred Scriptures are read in the Church, God himself speaks to his people, and Christ, present in his word, proclaims the Gospel.
Therefore, the readings from the Word of God are to be listened to reverently by everyone, for they are an element of the greatest importance in the Liturgy. Although in the readings from Sacred Scripture the Word of God is addressed to all people of whatever era and is understandable to them, a fuller understanding and a greater efficaciousness of the word is nevertheless fostered by a living commentary on the word, that is, by the Homily, as part of the liturgical action.[cf. Sacrosanctum Concilium 7, 33, 52]
Nothing really surprising here, right? Christ speaks to people through the proclamation of the Word. Homily: vitally important, too.
Catholic Sensibility 
Simply, beautifully put!
By contrast, the sermon in the preconciliar Mass was not considered properly part of the liturgical action.
If my memory serves me correctly, “low” masses never had sermons.
“High” masses, at least in my parish, had sermons with an inordinate faxation on the BVM.
That s/b “fixation.” In my days faxes were uncommon.