I'm surprised at how productive a good part of this thread is! Strange to see most of the arguing is between two Catholics, Eastern Catholics at that!
I'm guessing the Roman Catholic doctrine of inherited guilt comes from the theology on heaven and hell (or perhaps vice versa), and of course St. Augustine. Prior to Christ, all humankind went to hell. Even the righteous, even the infants; Elijah is the an exception. Since God is righteous and just, to be sent to hell would require sinfulness, some sort of "guilt", even to the sinless infants. For what would they be guilty of to be sent to such a place? If God truly is just, why would even the sinless be damned? I'm guessing it is along this line of thinking. I know St. Augustine was also very adamant about unbaptized infants being sent to hell. Therefore, if Baptism is necessary for salvation, then Baptism must wipe away the stain (guilt) of original sin.
And I understand the Eastern concepts of heaven and hell are
slightly different, though I am do not know the Eastern beliefs in pre-Christ afterlife. Romans will admit that there is quite a bit unknown about man's condition, and we aren't as adamant about original guilt as we're made out to be.
As far as the Roman Catholic Church changing their views on Augustinian original sin, I'm not sure I'd say its an honest, theologically thought out change. We all have to admit, original guilt isn't exactly pleasant to the ears. Since the Church has also abruptly changed its views on the salvation of unbaptized infants, non-Catholics, and non-Christians, as well as liturgy and sacramental rites, all at the rise of liberal theologians and bishops, I'm not sure I'd trust the changes [in Augustinian though] as genuine or permanent. Time will tell.