I think it is only natural that the 5D MkIII borrows much from the 7D, as that is the most recent semi-pro camera prior to the MkIII. As an owner of both the 5D MkII and the 7D, the ergonomics and layout of the 7D makes much more sense. When I tried out the MkIII when CPS did a demonstration, it certainly felt like I was picking up the 7D. As someone who shoots both landscapes and wildlife, eventually, I will replace the MkII and keep the 7D for extra reach or if I need a higher frame rate, using the MkIII for more than just landscapes, because of the improved image quality. If I got the 1D MkIV, then I would replace it with the 7D, but I would lose reach (although I'm betting that a 2x extender willl at least match the 1.4x coupled with the 7D, with the exception of CA and contrast).