Edge sharpening, like all forms of sharpening, should be specific to the image. Images with finer details like landscapes of autumn colors need different settings than images with large open spaces and little detail like clouds over an open ocean view or an image of the Grand Canyon or Mediterranean coast. I also think cameras with more pixels (eg. D800 @ 36MP) may require different settings than cameras with fewer pixels (e.g. D300 @ 12MP).