When we welcome the full truth contained in the Magisterium of the Catholic Church, that recognizes the mystery of the Incarnation of the divine by means of the human, the Blessed Virgin becomes the necessary path to redemption.
The Virgin Mary is the way God presents Himself to us: through her we can reach Him. The Mother, in fact, did not only give birth to the Son of God, she also accompanied him until the end of his journey. And she still does so today, as the encyclical "Redemptoris Mater" of Saint John Paul II states.
Therefore, when we reject the great importance that the Blessed Virgin has in our redemption (the same encyclical defines her as "Mother of the Son who is consubstantial with the Father and his generous companion in the work of Redemption"), the importance of Christ ends up being diminished.
In the work of Redemption, she is the mediatrix of men before their mediator, Jesus, and in addition to being the mother of Christ, she is the mother of the Church and of all humanity (as Blessed Paul VI says), who gives birth to us continually.