I've noticed it too. I suppose there's only so long you can bang out the same message before you begin repeating yourself. Also, judging from the GB talks I've listened to, the Society does not have the most intellectually gifted pool of writers to draw from. I suppose that's inevitable when you ban higher education!
An example of this endless repetitiveness is the "paint by numbers" approach to explaining scripture. The illustrations used in the magazines to explain basic concepts are insultingly simplistic. I'm losing count of the number of illustrations that involve doctors. There's yet another "doctor illustration" in the latest Study Edition (May 15th 2013, page 5)...
"Why should we, like Jesus, use questions in the evangelizing work? Well, consider this scenario: Your doctor tells you that he has good news. He can cure your illness if you undergo serious surgery. You might believe him. But what if he makes that promise even before he asks you any questions about your health? Then it is unlikely that you will have confidence in him. No matter how talented the doctor may be, he needs to ask questions and listen to what your symptoms are before he can give any meaningful help. Similarly, if we are to help people accept the good news of the Kingdom, we must master the art of asking effective questions. Only after we gain a clear picture of their spiritual condition can we assist them."
Of course, the irony of these constant doctor illustrations is that JWs are themselves banned from becoming doctors because higher education is so stigmatized. They are drawing on a profession to prop up their ideology that ordinary Witnesses can never aspire to joining.
In summary, the Society is pumping out this stuff in a total vacuum of intellect and creativity, and we are seeing the results.
Cedars