Considering that you are full with techniques, approaches and all that techical stuff, but still hungry for something more, something different. What else is left and where I can find that hidden knowledge? Here is an interesting excerpt about Selecting a Subject. That's kind of funny that we so rarely read or discuss what to shoot instead we talk about how to shoot, how to develop and postprocess the images. So this link would help you explore the other side of the photography coin.
Here is a quote about photography from the book: "The reason is that photography is only a tool, a vehicle, for expressing or transmitting a passion in something else. It is not the end result ... It comes down to the choice of subject. The photographer must have intense curiosity, not just a passing visual interest, in the theme of the pictures. This curiosity leads to intense examination, reading, talking, research and many, many failed attempts over a long period of time."