Mediatrix of all graces and co-redemptrix are not only unnecessary, but problematic and this hyperbolic language should be proscribed from use in any official Church documents.
Certainly we should honour Mary as Theotokos for her perfect obedience and sinless life, and as the mother of our Saviour, and as our own mother, given to us by Christ. But we don’t need to invent titles or demand new dogmas.
God works through His Chirch to expand our understanding of previously revealed truth.
While, I will acknowledge, some theologians are a bit out there, the Church typically does not “Invent” new titles.
Let’s examine a bit of the theology of Mary as Co-redeemer, Mediatrix of all graces.
Mary is the mother of Jesus. No one argues that. When we think of graces flowing we relate that to reception and celebration of the Sacraments, do we not?
Vatican II talks about Jesus, in His humanity, as the primordial or fundamental sacrament. Indeed, it was Jesus who, through His ministry instituted the Sacraments. The Sacraments we celebrate today are an extension of Christ’s ministry in time thoughout all time to all ages.
Mary, as the mother of Christ, is the mother of Sacrament, fundamental and primordial. Since God wills our participation in Sacraments as a means to merit grace, Mary is the co-mediatrix of all of these graces. Since it is through her “Yes” that we were redeemed, she is the co-redeemer. To flip that around, without her yes, there would be no redemption…
Mary is not God. Nor she we ever deify her. I am sure she would be the first one to correct us if we were tempted to do so. But, Mary has a unique role in the sanctification and redemption of mankind that no one else ever possessed.
I have authored posts that questioned the wisdom of ever making a proclamation regarding our Blessed Lady as co-redeemer. After much study and prayer, I am starting to soften a bit.
May the Holy Spirit guide you in your search for wisdom and truth…