Another problem I see in some Agile Methods is a lack of flexibility about the rules they propose. I see that as some kind of contradiction: for example, Scrum is empirical only for things that it does not define beforehand.
“Don’t change Scrum” is something that Ken Schwaber wrote in his book Scrum and the Enterprise. Here’s his rationale for this: “Scrum isn’t a process that you can modify to fit your enterprise. Instead, it exposes every dysfunction in your enterprise while you build products… Whenever people change Scrum, it’s because they’ve run into a problem, dysfunction, or conflict that they do not want to face and fix. Instead, they change Scrum so that the problem remains invisible and remains deadly to the enterprise. If you allow this to happen, you will have lost Scrum’s primary benefit”.