She is not a cause in the sense of the ultimate source. The Father is ultimately the source of all.
She is the cause of all blessings, however, in the sense that through her God took flesh, thus making it possible for us to achieve theosis and receive salvation. She, personally, is Again, none of this can ever be separated from the dogmatic understanding of the Church.
Yes, these things do make Protestants cringe. But again, these things are parts of our inner tradition. They are not something we emphasize as being at the center of our witness as we witness to the Christian faith.
When these prayers and services are experienced from within the totality of the Orthodox faith, they seem like the most natural thing in the world. Even to a former Protestant who was taught that Catholics were going to hell because they worshipped Mary. :-)
Do you honestly think an average member of your Church really understands that? Saying that she is the cause of all blessings is different from saying that all blessings were made possible through her bearing God as a Man. This kind of language does not favor serious involvement of laity in ecclesiastical issues.