As a Lutheran I do not have problems of calling St. Mary as the Mother of God, and I do not exclude the possibility of departed Saints praying for us. I think I also understand the theoretical difference between latreia, dulia and hyperdulia. I have reservations with the practice.
After reading Alphonsus Linguori (a Doctor of the Church) I get a strong impression, that he makes the Salvation conditional to the Mediation of St. Mary. He appears strongly to indicate that the prayer of St. Mary invariably turns away the wrath of her Divine Son.
Now, regardless the theological fine points of that type of supposition, to me it indicates that St. Mary is considered, if not more powerful, then at least more merciful and more perfect in love than Jesus Christ.
For a protestant like me, who has considered Jesus as the most human, most merciful God-Man, whose love for us cannot be ever fathomed or surpassed, the proposal that her mother, however humanely perfect and however sanctified, could love us more than He, sounds a step from hyperdulia to latreia.