Richard Harris does not quite work in this film...
I thought Harris was pitch perfectly cast for Sorcerer's Stone, where he embodies the type of wise, kind elder wizard that fits in perfectly with the soft, optimistic glow typical of a Chris Columbus film.
Now while Dumbledore doesn't have a great deal to do in Chambers, the film or the novel, Harris seems to barely be holding on. I do know that the man was ill, but there are scenes where his voice sounds literally a step above a death rattle, and he looks almost propped up in other scenes, barely able to move.
After watching Harris in many wonderful performances, I have to admit that it's just sad to behold him literally slipping away before one's eyes. It reminds me too much of watching the great Donald Pleasence barely able to make it through his own final performance in the last Halloween film he was to complete.