Hesychios,
That is all great about the eastern and western applications. But then let me ask you a question. If he is truly mirroring our Lady, why was he not assumed to heaven as Our Lady was? First I would like to say the John the Forerunner (or Baptist) is not mirroring Our Lady. Their stories are quite different and they cannot be compared.
In fact, a good argument could be made that John was understood as sinless well before Mary was even thought of as the Immaculate Conception, Gate of Heaven, etc.
Mary was not recognised by Catholics and Orthodox as sinless or special until Christology was settled, Before then the church was not even certain what the true nature of Jesus was. Was He fully Divine? Was He fully human? Was He both human and divine? Did He really die on the cross? Was He really resurrected in the flesh?
Mary became known to us as the God-bearer (Theotokos) once we understood that Jesus was fully Divine and fully human. The Christological debates raged on for generations and resulted in numerous schisms.
John was already understood to be special in scripture and the early church probably saw him as the great example to be followed, the best saint to be prayed to for help and consolation.
I am speculating here, but his icon may have been over the altar interceeding for us before Mary’s was, who can say?