Generating VisualForce pages from Page Layouts
This feature was introduced specifically for Visual Force developers to be able to jump-start the development of a page.
It is in no way designed to produce the end result, a VF page you actually want. However, it will help you save some time by providing a template for your future VF page.
Just run this feature using the page layout that contains the most of the fields you want to see in your VF page, and you will have a very good place to start.