Mary's a Uniter, Not a Divider
When I was younger & dumber I thought that the way to Christian unity was to de-emphasize the Blessed Mother, to hide her in the back of the closet so as not to offend, much as the apostles tried to avoid scandalizing potential Jewish converts who thought some things were unlawful when they really weren't.
Arrogantly, I thought that this "was the way Mary would want it," nevermind that Our Lady was never much interested in the way she would want things but the way God would. And nevermind that the Orthodox and other Eastern Christians have a strong devotion to Our Lady. Nevermind Lourdes and Fatima. Nevermind the Marian piety so evident in nearly every modern saint or near-saint I admire, including St. Pio, Fulton Sheen, Pope John Paul II. It's like God was trying to tell me something.
I'm sympathetic to the "scandal of mediation" but I've become convinced that's the way God desires it. When I was younger I was upset with God for not simply appearing to everyone individually, ala St. Paul on the road to Damascus. Yet he wants to use human instruments, including His mother. Which means that He will use Mary not to divide Christendom (which she never did in the first place of course; reformers such as Martin Luther were very devoted to her) but a way to bring Christendom together again. The big mistake is to assume our strategies will bring about unity. That will have to come from God and will likely come about in an unpredictable fashion.