What is wrong with current jazz/contemporary music piano books or methods, and why do these materials often fail when music teachers or independent learners attempt to use them?

• 1) They are written by jazz professionals who, while they may be extremely knowledgeable and respected artists, have minimal or no familiarity with practical teaching techniques or current pedagogical trends.
• 2) Lead sheets have simple notation, but a pianist needs complex preparation in order to succeed. Many approaches purport to teach how to play the piano in ridiculously short periods of time, giving students false expectations.
• 3) Teachers often wonder if they are lacking in some way, due to their own lack of success in playing from lead sheets, when the resulting arrangements actually don’t sound very good. They’re accustomed to hearing composed art music, which possesses a pleasing texture and harmonic structure of great integrity. Teachers will not settle for a thin sound, and need to learn arranging techniques themselves.
• 4) Jazz books have improved a bit recently in terms of having a logical learning sequence, but most still introduce way too much material way too soon.
• 5) There is not enough preparation and reinforcement of concepts learned in just about all jazz and pop books written for students.