I would say the dark side of her story is the utter misfortune of trusting and taking sprirtual counsel from a predator.
I've blacked out his name, but her confessor was finally convicted of years of misuse of innocent victims. The Judge was so disgusted by his lack of remorse she ordered the max. sentence.
I am aware of Mother Teresa's modernist stuff, but it seems unfair to not hold her Confessor responsible for leading her astray.
I know she was good friends with Rama Coomaraswamy for years and years; I think they argued back and forth.
I say let's let God judge Mother Teresa's dark side. Wasn't Christopher Hitchens used as Devil's Advocate for sainthood?
Maybe the dark side to Mr. Terersa is the New Saints for a New Religion, but I don't know.