"There is no risk, in the perspective I have identified with that of "mariological synthesis", of Mary being regarded as some kind of fourth divine Person alongside her Son. The privilege of divinization is offered to all of us: Mary is simply the one in whom that process is already completed, having been prepared for this by her exemption from any of the limitations imposed by sin. It is represented for us most clearly in the final glorious mystery of the Rosary: the Coronation of Our Lady as Queen of Heaven and Earth. Through the Coronation of the Virgin Mother of God our own "royal priesthood", our own theosis, is made possible."
Great article on the relationship between Mary's coronation as Queen of the Universe and theosis.