His character work is underrated. People say his characters are archetypes, but I’d argue they are archetypes done excellently. They serve the plot and the historical theme, yes, but they have clear motivations, flaws, and arcs. Lady Maud in 'The Pillars of the Earth' is a brilliant study of a woman navigating a brutally patriarchal system with intelligence and grit. Ethel Williams in 'Fall of Giants' evolves from a maid to a Labour Party activist, embodying the social changes of her era.
They might not be endlessly introspective, but in an epic covering decades and dozens of characters, that level of depth would grind the narrative to a halt. Their clarity is a feature, not a bug. You remember them, you root for them (or despise them), and their journeys illuminate the times they live in. For a plot-driven epic, that’s exactly what’s needed.