But, like all art, it still ultimately comes down to whether a person likes it or not. You can break down and categorize all you want, but the perception of quality is still a very subjective thing.
Case in point: you do not like how The Witcher handles itself. Many people do. Both are valid opinions, but things get obnoxious when one party tries to claim that the other is objectively wrong.
For art to be art it must past objective deterninations of quality. Subjective doesn't enter into play until the objective barrier is passed.
We can have a subjective conversation comparing Maniac Mansion, Myst, Baldur's Gate 2, Command & conquer: red alert, Civilization, The Last of Us...
Games which have narrative techniques that pass the objective qualities we need to analyze before reviewing them as art. With games this is more complicated because things likr Xcom/Civ/SimCity/D:OS have emergent narrative elements that become part of the story. These are the games that fully realize what the medium can be. Minecraft is an example of a different way...emergent narrative that can become self authored pure storytelling/creation.
The games that don't have this need be objectively observed for the basics of style and language. Would you really claim a story written with the decision trees of an adolescent brimming with magical power in a grown man's body are objectively well thought out? That character is a villain, an idiot, or hopelessly lost. It shows no long term consideration for the character and his existence; it is a vehicle for the player to enact their power fantasies upon the game world without moral consiseration.
This is not 'morally grey' writing. It's morally absent. Consequences within the game world don't resolve the fundamentally pisspoor writing that must exist for the character to even think those thoughts in the first place.
Things can be popular and even critically well loved but completely fail all objective qualifications as art. Most hollywood movies are no longer art; they are made by teams of producers, marketers, focus groups and writers to create a product. The Witcher is a product. A work of artifice, not art.
It's fine if you cannot separste the two. Modern society has blurred the lines between them and games sadly have become more artifice than art.
But to pretend that such tripe crap is on the level of a great piece of game writing...is intellectually dishonest. It's skipping the step called 'objective critical analysis' and responding out of emotions.
It'd be like if I told you Haruki Murakami or Cormac McCarthy are strictly better writers than Stephen King/Dan Brown...and you still argued because 'taste is different' that there was no data to support that contention.
You can like something that's not art. I love loot games. No loot game is art. They are all dopamine pandering timesinks. Titan Quest is one of my favorite games...but not one of the best games. It takes effort to create a division between personal opinion and analysis.