But there is no consequence to it. You can only do it within the context of A is the 'good' choice and B is the 'evil' choice. Morality in real life is no so black and white as it is presented in Bioware games. As slimgrin says, more and more developers have realised this and embraced a more complex system that doesn't judge the player, simply presents them with the consequences of their choices but Bioware retain the same system they were using over a decade ago. Gaming moved on, Bioware haven't.
In the example you give, you are knowingly freeing a Mass Murderer, equally knowing there is a high probability of re-offending. In the example I give from TW3 you don't. You think you're doing the right thing by saving someone from being killed. You have no idea he will go on to commit mass murder because you are not told he's a mass murderer. He's simply someone you can either choose to help or not as your conscience dictates. That's the difference in Bioware games.
There are consequences in every single one of the four examples I referrenced, and absolute none of them are presented as involving a black and white understanding of morality. Even in the case of paragon and renegade, which are often denounced as inconsistent and flawed, it's never been about the good choice versus the evil choice.
Now if you don't think those consequences are significant enough, that's your prerogative, but the example of consequences that you provided involved the death of background characters in the fictional world. You established the qualifications for what you consider to be real consequences, and Bioware has already met your qualifications numerous times, well before TW3 came along.
Kelder Vanard is a remorseful serial killer of children in DA2 who begs you kill him. Most of your companions consider it the best choice and reward you with more approval if you do it yourself. He also very definitely continues to kill if you let him live. But if you do kill him, you must take on the role of judge and jury, and execute him in cold blood. You also must completely sacrifice any goodwill you had with his father, the Magistrate who hired you to return him. There are several potential problems here. First, what if the player character doesn't believe in killing outside of self defense or believe that they have the personal right to condemn a man to death? There's also the matter of self interest, and protecting your family. You're a poor refugee who either is an apostate themselves or is sheltering an apostate sister. Your position is precarious, and making and enemy out of a Magistrate is an extremely dangerous idea.
In DAO, whether you kill or recruit Loghain, someone is going to think you made the wrong choice. Recruiting him means you lose another companion, so there is a consequence. It's the job of the player to decide whether that consequence is a acceptable loss for them. The reasons for sparing can be practical, idealistic and forgiving, or even punitive, if the player thinks killing him lets him off too easy.
Killing Anders gives him precisely what he wants and turns him into a martyr for his cause, while sparing him leads to, as I mentioned, an actual war between two city states.
However, the example from a Bioware game that most closely resembles your Witcher example is probably Rana Thanoptis. We know she's been up to some shady stuff both times you meet her in Mass Effect 1 and 2, but she always offers excuses. We have no hard evidence that she's a direct danger to anyone, any more than anyone else you meet in the galaxy. In order to kill her, you must kill her in cold blood. If you let her live, she turns out to be indoctrinated, and you find out that she kills a lot of people in ME3.
The remaining distinction is that, in your example, Geralt doesn't have any context for why the person he frees is tied up, while the Bioware protagonists in my example are given more background. His choice is to either leave a stranger bound and helpless, or free him.
I'd argue that particular lack of context doesn't, in fact, contribute to a more meaningful moral dilemma. It does perhaps contribute to a sense of grimdark, because it's a well meaning, good samaritan version of Geralt that ends up indirectly causing more death and suffering. But the choice that's presented to him has far fewer ethical and practical variables that any of the simillar examples in Bioware games.
It's cool that you like this thing in The Witcher, but the truth is that Bioware has already been there and done that several times over.