It seems beyond dispute that, properly understood, Mary is a Co-Redemptrix.
We are all co-redeemers. We do not redeem ourselves, but we have the honor and privilege of joining our suffering to Jesus’.
Mary was unique in her role as Co-Redemptrix in that she was able to cooperate in ways that we could not. In a sense, she initiated Jesus’ mission at the wedding. Jesus could not deny her. I can’t help but believe that she had at least some vague sense of the loss and pain that awaited her (Simeon certainly gave her a warning). If, at Jesus’ scourging and crucifixion, she had called upon her Son to stop it, surely scripture would have recorded it. But she did not. Rather, she undoubtedly willingly suffered tremendous anguish. I think that meditation on the Sorrowful Mysteries can sometimes evoke a profound sense of Mary’s suffering as well as Jesus’.
Would a formal doctrinal declaration of something that is not actually in dispute in the Church, serve to aid people in understanding our own roles in the redemptive value of suffering? Would it only serve to sow confusion? Unique as was her role, Mary also needed to be redeemed. Her conception without sin was obtained by Jesus’ future sacrifice. Will this point be understood or lost in a formal declaration? Has the Holy Spirit been moving the Church to declare this? Have APPROVED apparitions truly suggested that this doctrine should be advanced?
I don’t know that we ought to care what protestants will think. There is much to be admired about the vigor of many protestants, but they are laboring under much error. If they don’t embrace their mother, given to them by Jesus from the cross, that is not a reason for us to be reticent about our embrace of our mother. But if the doctrine, which ideally should serve to bring clarification to important issues, actually creates confusion, criticism for the Church’s COMMUNICATION of the doctrine (not its soundness) would be well-founded.
I am not fully formed in my opinion on this yet, but I found this “pro” Fifth Marian Doctrine writing easy to read and helpful.
voxpopuli.org/response_to_7_common_objections_part1.php