Leliana's characterization has always been somewhat suspect. Bioware can't decide who she is and she switches back and forth instead of developing (like Morrigan did for example). Why does her storyline always end up with her needing to be influenced by someone else? Didn't we go through this already?
Mmm...it's always been Leliana story.
She's never been a mentally stable person even in Origin.
She used to creep me out back then.
She giggles and tells you how she enjoyed seducing and killing people , she never had a problem with what she was doing.
Also she's broken up about being betrayed by a BARD.I mean yes they were lovers , but Leliana did the same thing to all of her victims.
She's saved by Justinia , suddenly end up a lay sister and think she's the Maker Chosen.
Then the warden can soften her .
Or harden her , and she will confess she was bored as a sister.
Again whatever happens , she goes to the Divine and is used like a tool for years.Out of blind devotion , Leliana again kills willy nilly.
Then the Inquisitor can again change her or push her further down the rabbit hole.
I mean in 10 years , she went from a ruthless bard because she loved Marjolaine.
To a cheery chantry sister , because she loved Justinia.
Then whatever your warden choose for her.
Then Justinia turns her into a ruthless killer again.
Then the Inquisitor can influence her.