From a recently published Wired article:
[Allen] realizes that his system can be difficult and that he's often accused of going overboard with elaborate schemes. He responds with a shrug. "Look, the workings of an automatic transmission are more complicated than a manual transmission," he says. "To simplify a complex event, you need a complex system."
This runs counter to my personal experience with the Getting Things Done (GTD) system. It seems that this system works well if you fully commit to it as well as if you only partially commit to it. That's the beauty of GTD. There is something in this productivity system for everyone. Not just those looking to become hyperefficiency nuts.