One of the issues you often get in Open-World RPG games is that there are a million side quests, and pretty much all of them are "hey, I want this thing. Go to this cave and get this thing and come back and you'll get gold and pants." While they put a little effort into giving some backstory to the McGuffin, often it's a simple matter of going there and picking something up.
Now, to be fair, I've only played through a bit of the Witcher III. I'm in Velen (wondering if I should head back to White Orchard and make sure I've fully explored there,) and I think I've gotten to a serious midpoint of the area (quests are now sending me to Novigrad, which is the big city in the area that I haven't even come near yet.)
It's possible that I'm just not wise to the familiar patterns that Witcher side quests will fall into. But so far, I'm really impressed.
Being a Witcher means being a genetically enhanced monster-hunter (despite being a pretty straightforward medieval setting with countless tiny villages dealing with monster infestations, people seem to understand stuff like DNA to a greater extent than even we do today,) and that means that even though Geralt's got his own main concern (finding his badass adopted daughter Ciri and protecting her rom the eponymous Wild Hunt,) he pays the bills by taking on Witcher Contracts and also helps out people he meets along the way.
The great thing is that even the Witcher Contracts - given their own special category apart from Side Quests - which are your classic "kill this one monster" sorts of missions, are given a decent backstory and a few twists and turns. You'll often have to track down clues to help you find the monster (admittedly, this mechanic is not the greatest, especially given the way you need to point the camera and position Geralt just right to make him interact with the correct object) and talk to villagers, then hopefully identify what the thing is, allowing you to use the quite clever crafting system to put together the right potions and oils to get ready to face the monster down.
And sometimes, the monster is more complicated and you are forced to make a moral choice. But this isn't like Bioshock, where it's between total sociopathic cruelty and altruistic benevolence, or even Mass Effect, which has a somewhat more subtle dichotomy of ethical paragon or expedient renegade, which is still a clear set of categories to put your choices into.
Geralt has real serious moral questions to answer, and the "right" option, or even the "officially good" option is not at all obvious. For example, there is a side quest in which you are hired by a hunter to track down his wife - she was happily married to him, and was unlikely to run away, but she has gone missing in the woods.
When you search for her, her sisters (who appears to live with them) approaches and tells you to just tell the hunter that she's dead and let him move on with his life. You can take a bribe from her to do this, but if you continue your investigation, you'll find that she was killed by a werewolf. You can track the werewolf to a hunting lodge in the woods, and if you go into a cavern beneath it, you'll find the beast. However, when you fight it, just as you're about to kill it, the woman's sister arrives and tells you to stop - that the werewolf is actually the hunter, and that he didn't know that he had killed his wife.
The hunter had been going to this lodge and locking himself away to protect people from himself when he was transformed. But the sister had fallen in love with her brother-in-law, and she decided to show the wife what her husband really was, hoping that she would run off in fear. Instead, the werewolf broke free and killed her.
So here's the moral choice you're presented with: the werewolf/hunter finds out about this and resolves to kill the sister in revenge. Do you let him? In a sense, she killed her sister by proxy via werewolf, but she never intended to do it. Yet she was still responsible for the death, and let's also recall that she was trying to destroy her sister's marriage.
The hunter had specifically gone to this cabin to avoid hurting anyone, and while he clearly did not think out all the contingencies, he was making an effort to keep people safe. But the fact remains that he is a dangerous monster, and now he is threatening to kill this woman who has wronged him.
It's a tough call. I decided that once the werewolf started killing people intentionally, as justified as he might have been, he'd no longer be eligible for protection from my monster-hunting wrath. That, and also that killing this woman would not bring his wife back, and he'd still live out the rest of his life knowing that he had killed his beloved wife. The sister might have a chance to repent. So I killed the werewolf.
You might argue that this was, in fact, the "officially good" way to resolve the situation, but it required real moral interrogation, You could make the argument that the real criminal here was the sister, and perhaps she deserved a just death.
In case you're worried that I've spoiled something major about the game, take note: this is one side quest among many. These people are not major characters in the story. It's just a basic "track down this monster and kill it" kind of quest. But it's invested with real story stakes in a way that I don't think I've ever seen another video game put in a side quest.