No Mary, no Incarnation; no Incarnation, no death on the Cross; no death on the Cross, no Resurrection; no Resurrection, no salvation for the world. Get rid of Mary and you don't get a purified faith: you get nothing. That is the consequence of overlooking this often neglected truth.
(UPDATE): Steve Dillard at Southern Appeal has a short post with links about the subject at hand. Check out the comment box; a great dialogue is taking place, including comments by Jimmy Akin and Mark Shea.