"Mediatrix" is much more understandable, and is easily related to our own role in bringing Christ to other men. We have that concept clearly defined already.
So, why not leave it at that?
I thought the explanation was pretty clear, co/cum means "with" not on an equal footing but in a subordinate fashion as Paul says:
(Col 1:24): "Now I rejoice in my sufferings for your sake, and in my flesh I complete what is lacking in Christ's afflictions for the sake of his body, that is, the church,"
Mary's sufferings are efficacious towards the redemption of man because they are wholly rooted in the redemptive graces of Christ and are perfectly united to His redeeming will. Similarly, as Mediatrix, the Mother of Jesus does not "rival" Christ's mediation but rather participates in the one mediation of Jesus Christ. Imagine water from a reservoir reaching the people through a system of aqueducts or channels. By analogy, Jesus is the infinite "reservoir" of all grace, which is distributed to us through Mary .... as she gave birth to Jesus. Jesus, the one mediator, does not exclude secondary, subordinate mediators.
This is pretty clear, I think its easier to explain than the Assumption, but that's just me.
By the will of the Holy Ghost, I am in acreement with you here.
Yeah. I'm skeptical that the precise definition of "co-" will EVER sink in, even though the theology is clear.
We suffer from a lack of precision in definition...