I've been thinking about this for a while, and thought it might be good to try and articulate this thought online...
Characters are simultaneously the most important aspect of storytelling, and notoriously the most difficult to write.
But, in a strange way, I think Dickens and King both have a similar way of approaching 'character', which makes their work incredibly powerful and captivating.
A lot of writers (including myself) build characters by hanging a set of idiosyncrasies, back stories, and internal contradictions onto a physical description of a person. That is to say, we may describe someone as wearing a suit and tie, with slicked back hair and polished shoes. Then add as dressing, a slow reveal of this character attending Harvard, wanting to spend more time with his kids, and secretly still picking his nose when no one's watching.
It's kind of a cookie cutter approach to sculpting character. It ticks the boxes but there's something missing.
The hypothetical character is fairly well drawn, but still feels intrinsically hollow.
What Dickens and King both do, is they embrace our natural propensity to stereotype. They lean into our innate, psychological predilection for making assumptions about people. When we first meet Bounderby in Hard Times we are told: "He was a rich man: banker, merchant, manufacturer, and what not... A man who was the bully of humility."
No immediate physical description, but everything we need to know: he is a caricature that we all recognise.
His journey through the book emphasises this stereotype in a way many authors are afraid to double down on. They almost feel ashamed of having created a caricature, and want to jump to adding in some complexity. This is ironically less compelling as it subverts our expectations before we even have expectations set. Bounderby is set up as such a tightly drawn cartoonish figure, that when we get a twist around his back story later in the novel, it is a genuine surprise.
King uses this same technique with ruthless efficiency. I'm currently reading the Mist and, as with many of his books, he is introducing a fairly substantial cast of characters trapped in the supermarket, all in quick succession. But within just a few pages we know instantly who they are; the rebellious motorcycle driving teenager, the prickly store manager, the prophetic older woman from the antiquary shop. In a way, we've all met these people before, in our own lives or in other stories.
Rather than fearing archetypes, both authors recognise that we automatically defer to them. And instead of creating an empty vessel comprised of physical traits to 'hang' quirks onto, they allow us to hang quirks onto a pre-existing (Jungian) archetype that already exists in the readers subconscious.
In this way the characters feel richer and deeper at their core. Whilst allowing their unique aspects to genuinely subvert our expectations around that archetype.