Plaster on a wooden leg
As I see it, Agile methodologies are an answer to the wrong question.
The problem does not lie in development methods, but in the inability of the client to express his/her needs, and in the inability of the project manager to understand and translate them. It's all about communication and psychology. Learning to listen, to understand, to be open minded would help, alas IT people are most of the time antisocial psychopaths (count me in).