Gentleman:
... "What is the re-interpreted original sin"....
I think it is not 'original sin' that it to be 're-interpreted' -- just all the thinking and theological constructs that we have built up around it.
There was no "Adam and Eve" to commit that "original sin". So we need to start over.

The myth describes and presumes the 'nature' of our experience. It pictures an 'original' nature where to prevent the destined death they would have had to eat of the magic tree of life. They sinned very easily, because the fruit looked and tasted good and 'my wife served it'. Death and propensity for sin are already there. That's  our 'human nature'

That 'former' nature seems much like the 'fallen' nature. Yes, if we have free will, it is 'natural' to misuse it. "fallen' nature is just our excuse. eg: blame the snake, blame the wife, blame the first parents & 'fallen nature'. 

Jesus saves us from ourselves by teaching, showing us a better way to live. "Love one another as I have loved you"