Its really good for hardened Leliana. While its a bit sad, its good for her. She sees the true face of Thedas and life and deals with it accordingly.
Also it fits her duties as left hand, I mean Cassandra doesn't even know what were Leliana's duties but she trusted her a lot and knew she was doing them for the divine.
BTW I don't know what Bioware thought when they made softened Leliana ending. "One day she gathered them all and talked with them and they all agreed". WHEN did that happen
, whether in Thedas or real life.
Hardened Leliana however? Its quite real. Knowing the secrets of every noble, threats and blackmail and having agents everywhere is pretty much everything one needs in achieving her epilogue, and she has them. Ironically on my first playtrhough I had more secrets perks than others so the ending fit Leliana becoming divine. All about intrigue, cunning and espionage. First try to reason with people peacefully, if it fails blackmail/threaten them, if it fails they will find a dagger on their throat. Its not "nice", but Thedas is not nice either.