Immaculate Conception

This feast day is hard for me this year. I have a hard time making sense of the Immaculate Conception. As far as I can tell the Church does not require that we accept Original sin in the narrow sense that we are born with the stain of sin on our soul, we merely must accept that we are born with punishment of Adam's sin on our soul. This is the position of the Christian East (i.e. Eastern Catholics, and Orthodox). They do not accept Augustine definition of original sin, that we all inherit the sin of Adam. So we are born as sinners under Augustine's conception of Original sin. The East speaks of Ancestral Sin. That is that we inherit the punishment of Adam's sin but not the sin itself.
The Catholic Church, as far as I can tell, does not require Eastern Catholics to accept Augustine's vision of Original Sin. So my question then is if this is the minimum bar the Church holds us to on the issue of Ancestral Sin, then from that vantage point there is no good reason why the Immaculate Conception is necessary. If all Mary would have inherited is the punishment of sin, that is death and suffering. She clearly suffered and even in the belief in the Assumption there is the tradition of Mary first dying (i.e. the Dormition) and then was assumed. But if that is all she inherited then by the Grace of God she could have lived a life free of sin without being Immaculately Conceived.
For me then it is hard to make sense of the Immaculate Conception. I will not deny it, but I have a hard time making sense of it. It seems unnecessary, but perhaps I am missing something or misunderstanding something. Feel free to correct me if you stumble upon this blog and see a problem in what I am saying.

Speaking of World War Two...

Mother Bernardine Goulter shares her story of surviving the Atomic Bombing of Nagasaki. A city founded by Catholic Missionaries and at the time of the bombing 2/3 of all Catholics in Japan lived in Nagasaki. In fact the Catholic Cathedral was the target used for aiming the Atomic Bomb. Out of this untold misery may we pray that we as a race have learned never to use such weapons again. Mother Mary, pray for us.

"No matter what people say about the atomic bomb bringing the war to an end, of its preventing wars in the future, never can I be reconciled to the injustice inflicted on thousands of innocent people whose only part in the war was to suffer from it." -Mother Bernardine Goulter