I registered my forum account so I could share on this topic as well, as it did concern me.
First of all, I want to make it clear that I am a big Bioware fan, and that I love DA:I so far, but when I reached the quest where Leliana goes ruthless it really unsettled me.
I really like Leliana, and I never wanted her to go down this path.
I do not object to the fact that your decisions can make this happen, or even that she is ruthless by default. I felt instinctively that both were the case.
My issue is that I have chosen soft, sympathetic, moderate, compassionate choices in every choice my Inquisitor has made, particularly to her, and then I get to this quest and she acts the same as if I had been telling her to kill everyone I came across.
I had no idea where I went wrong, and at first thought that maybe it was unavoidable, which sucked.
What sucked more was finding out that it was perfectly avoidable, but that the choice was so long ago, was so easy to make wrong, and was so easy to not realise its importance.
Seriously, I'm used to choices like this in Bioware games, but I never expected it so soon. Like others have said I didn't feel I had the place to tell her to spare the vile traitor so early on.
If It had been clear that there is NO WAY to soften her if I hadn't spared him, I would have.
If there had been anything mitigating about the traitor to suggest leniency was anything but an injustice to the dead people he betrayed, I would have.
If it had been later in the game, when I knew her better, and felt I could confront her on the issue, I would have.
If the result hadn't come 20 hours later I would have reloaded and tried again. Instead I have to go on with a bad taste in my mouth.