Fr. Florovsky was certainly one of our greats. He was quite firm in his criticism of Russian theology, especially of the 19th century, which he felt had been heavily influenced by scholasticism. The piece you cited is interesting, if a bit arcane. From an Orthodox perspective, although Florovsky is interesting, the patristic understanding set out here:
http://www.ccel.org/ccel/schaff/npnf204.vii.ii.i.html
is more beneficial to the advancement of Christian understanding of the Incarnation.
“As you noted, this places Mary Theotokos above all creatures as the unique Mediatrix with Christ the one Mediator. She is second only to Christ and her role depends entirely upon the one mediation of Christ the High Priest.”
Indeed she is, by grace, though she was born and died fully human and in need of a saviour and the great Mystery of the Incarnation...just like the rest of us. How does the title of “Co-Redemptrix” add to, or more dangerously, better define, what The Church already believes at all times and everywhere? Is this to address some problem endemic in the Latin Church which we in Orthodoxy don’t have?
“Through the prayers of the Theotokos, Saviour save us!”
It goes beyond scholasticism. It actually delves into Protestant heresy. For instance, Russian Patriarch Philaret in the mid 19th century issued a Catechism of the Russian Orthodox Church in which, at the very beginning he writes in the introductory note that the only true Old Testament is the Hebrew language version, which is even echoed today by some OCA churches! (the Orthodox Churches use the Greek-language Septuagint and "apocrypha" as the authoritative source).
It was Peter the Great and his fascination with things western, and western royalty (Catherine the Great), which brought much of the western religious flavor to Russia in the 18th century, along with powerful influence and Uniate conversions of traditional Orthodox lands (from Herzegovina in the Balkans to Ukraine and the Carpathian regions) brought by Maria Theresa of Austria.
We should also not neglect the seed of poisonous western influence in the phenomenon of Cyril Lucaris I, Ecumenical Patriarch of Constantinople, who embraced Calvinism in the preceding (17th) century, or the westernizing damage done by Meletius IV Metaxakis in the early part of the 20th century, during his two years as the first among equals in the Orthodox Church (among other things, he "recognized" Anglican Holy orders as "valid," uncanonically proclaimed "re-union" between the Orthodox and Anglican Churches, and equally uncanonically introduced western cadlendar that effectively divided and still divides the Church except for Pascha).