I wouldn't want to quibble about which feast is bigger or better. That sounds to me like the corporate world and not the way Jesus spoke when he was on earth.
But the Church does assign greater or lesser importance to feasts, thus facilitating their celebration. These have been simplified from earlier times and now are categorized as solemnities, feasts and memorials.
Solemnities are given the highest designation because they celebrate beliefs, events and personages of great importance and universal significance to salvation history. They begin their celebration the evening before with Evening Prayer I.
Ten of these commemorate some truths or events regarding the persons of the Trinity, including the feast of Corpus Christi, while three are for Mary and four for saints.
Feasts are next in importance. They begin at midnight and therefore, have no specific evening prayer the night before.
Ranked third are memorials. Saints' days which have a greater importance for the whole Church are "obligatory" memorials while others are classified as "optional."
The emphasis used to be placed on ancient saints but now room is made for celebrating recently canonized saints and those of importance to a country or region.
Easter is, of course, the most important solemnity because it is the summit to which the whole of our Christian life tends. Its octave includes the following Sunday (sometimes, called Low Sunday), thus giving two Sundays to Easter.
The Sundays between Easter and Pentecost are said to be Sundays "of" Easter and not "after" Easter to recognize the importance of Easter as a season.
Christmas is second only to Easter in importance. Both of these great solemnities have eight-day celebrations, that is, octaves, as well as preparation periods, that is, Advent and Lent, respectively.
In honour of the Resurrection of Christ, Sundays are ranked as the most important holy day of all. Therefore, only solemnities or celebrations of the Lord can take precedence over Sunday but even they cannot take over the Sundays of Advent, Lent and Easter.
Only four celebrations are permanently placed on a Sunday: feasts of the Holy Family and the Baptism of the Lord; the solemnities of Holy Trinity and Christ the King.
In countries such as Canada where the solemnities of Epiphany, Ascension and Corpus Christi are not holy days of obligation, they are assigned to Sundays.
It is, therefore, clear in the General Norms for the Liturgical Year that Easter and then Christmas are the two most important solemnities. The 15 other solemnities are of great importance also but they do not compare to Easter and Christmas.
In addition, one could say that without Christmas, neither Corpus Christi nor any other feast of Jesus would exist.
We celebrate other events in Christ's life to offer honour and adoration to God but also to help us focus on what Christ has done for us and how we can respond to that great love.
Feasts do not compete with one another but all are there for our spiritual enrichment.
Recently, I heard a speaker say that Corpus Christi is a bigger feast than Christmas. Is that true?