so, you would call her Christokos? Mother of Christ?
That would get closer to the matter, true.
The term "theotokos" suggests the heresy on the Trinity known as Sabellianism. Sabellianism posits that all three Persons of the Trinity are really just sequential "manifestations" of God, but would not be co-existing Persons. The closest modern example would probably be the Oneness or "Jesus Only" Pentecostals, who reject the traditional Trinity in favour of God's manifesting Himself as ONLY Jesus (though some say ONLY the Holy Spirit). The Sabellians in ancient times were also known as Patripassianiasts because of their belief that the Father suffered on the cross - a result of their belief that the Father, Son, and Spirit were not separate Persons, but only "masks" that God put on.
The term "theotokos", meaning "God-bearer" implies Sabellianism for the same reason that the ancient Sabellians were called Patripassianists. Saying that Mary was the "GOD bearer" suggests that "all" of the Godhead was carried by her - which would suggest that Jesus was a "mask" of the Father, etc.
The term "Christotokos" can be heretical, if it is meant in the way the Nestorians meant it - which is to say that Christ was not really God. However, the term can also be entirely orthodox, if we understand it in the sense of the Biblical truth that Christ, as Messiah, certainly was the Son of God, the Second Person of the Trinity. And Mary did indeed near Him, though she did not bear the Father and the Spirit, as the term "theotokos" could imply.