GTD: Not a complete system?

An interesting post today on O’reilly about one of the limits of GTD: it doesn’t have a rule for deciding if you actually want to take on the work or not.  The up front filter asks the question “Is this actionable”.  Maybe if it were changed to “Do I want to do anything with this?” or “Does this help me reach long term goal?” it would get closer to the ‘productivity nirvana’ the author is looking for.
The Limits of Efficiency