Excellent analysis. More people should ask themselves just what it is that they are trying to accomplish with their photography.
I too find AA's images while "pretty" are generally devoid of any intellectual stimulation beyond the technical considerations of making the image. Although one must keep in context the motivation for his photography. Initially it was to showcase the beauty of nature so the conservationists could use his images as ammunition in their efforts to save the parks or establish new ones. For this he was successful.
On the other hand Weston's images showed in my opinion a far deeper intellectual analysis and representation of a message. His type of "pre-visualization" was much different and again in my opinion much deeper than AA's. Weston went beyond the shear mechanics.