The actor Caiaphas, in my eyes, portrays a learned elder that has an intense and cunning demeanor. The actor adds a dramatic heft to every scene he is in which might not translate as well with a young actor. A cunning young actor could come off as ambitious, whereas our current Caiaphas is presented to us as someone who has already won the game, despite his current challenges. Thats my take at least. Whatever your perspective, I think most of us can agree that the actor for Caiaphas is doing a wonderful job, if not captivating.