It truly is a great conundrum. I wonder if "original sin" was the way that the ancients explained their observation that bad and incomprehensible things just happen for no apparent cause. 

Suspending knowledge and reason to uphold shaky theological principles seems to be like the servant who buried his talent for fear of losing it. Risk and change are part of this story and not a sign of unfaithfulness at all.

Interesting that the Orthodox, who do not believe in the IC, also believe that Mary truly died.  If death is the consequence of original sin, this suggests that she was subject to it and the entire messy human experience like the rest of us. Personally, I think the notion of the IC is a distortion to save the Madonna from a twisted theology that presumed that sex is corrupt and the normal female body is inferior, and not how the early church believed at all. She's easier to admire as one who was not specially privileged and still open to God in all things.