The character himself may be well, or a least consistently written - but our capacity to react or respond to him is not; It's like having a play where one actor is a professional thespian, but they're acting against a large sheet of cardboard with a stick figure on it; it doesn't matter how much attention you give to getting the professional character, and how focused you are on getting them believable, consistent, immerse and compelling; the scene itself still falls apart entirely as long as the other half of the cast is so stunted and lacking in nuance.
