As an Orthodox Christian, I do not change doctrines or terminology to fit fashion. The mind of the Church understands 'Theotokos' to clarify and guard the same truths now as in 431, 'Christotokos' still denys them. Nor does the Church insist that the canon of Scripture, our primary written testimony to Christ, to God, and to the history of our salvation is exhaustive.
Some of your complaints about Latin mariology are just, though you probably frame them for the wrong reasons. We Orthodox regard the 'Immaculate Conception' as a jury-rigged fix to paper over a disconnect between the Latin (mis)understanding of Ancestral Sin (termed 'Original Sin' in the West) and the Church's long teaching concerning Mary's purity. While we're at it, though Mary was, indeed, assumed bodily into heaven, it was after her death (a point the Latin declaration of the dogma of the Assumption deliberately leaves ambiguous, as a large faction among the Latins hold that she did not die. As I understand it, it was concern for a hoped for reunion with the Orthodox that restrained the Pope, who himself held the view that Mary did not die, from including language to that effect in the proclaimation.)
There is an Orthodox objection particularly to the conjunction of the Immaculate Conception and a deathless bodily assumption, as it makes Mary nature not ours, but a pre-lapsarian Adamic nature. 'Not assumed, not redeemed' was the cry of the Fathers against monothelitism and monergianism, on which basis, I would argue that Mary's nature being other than ours vitiates the basis of our salvation as effectively as separating Christ's person or denying either of His natures.
Nonetheless, the tradition of the Church is that Mary (and the Prophet, Forerunner and Baptist John), while not sinless in the sense that Christ is sinless, nonetheless did not commit personal sin. (I have a dispute with my priest, who takes the more extreme view that this includes involuntary sins as well as voluntary sins, while I incline to the view that it includes only voluntary sins.) It has also, always been the understanding of the Church, East and West, that she was preserved from the pangs of childbirth (which the Fathers associate with the passions and the engendering of children through sexual intercourse, so if you'd like a Scriptural text to support the Church's position, look in Genesis), but experienced their anguish and more when the 'sword pierced through her heart' seeing Him on the Cross.
As a non-Eastern Orthodox Christian, I see none of these things in the Mary of Scripture, so I reject them.
In theological circles, one may do well leaving it as Mother of God. But we live in a generation that doesn't even understand what the Incarnation is and think that Jesus is just some guy on a cross or just a baby in a manger that we think of twice a year. Things have to be clear if the gospel is to reach people. They have to be broken down. I understand that by calling her Mother of God you do not mean that she preceded Christ's divinity. But would a non-theologian realize that? Someone pics up a book just on Mary. It isn't particularly a theological book, but it offers a devotion to her as Mother of God. What are they going to think?
Paul, when he preached to the Athenians, broke it down into their language. The language was unequivocal.
In this day and age of sound bites, we don't always have that luxury.
Jesus. All God. All Man. Born of a Virgin. Crucified to pay the penalty for our sinning. Resurrected to give us life. Sitting at the right hand of the Father interceding for us. Coming again for us in power and Glory.