Is the PDFEdit layer robust enough to use for higher level editing of PDF files, as opposed to using the content streams directly?

The PDFEdit Layer (PDE) of the Adobe Acrobat API contains classes that provide for editing in PDF documents including colorspaces, clip and page objects, fonts, form XObjects, and other objects.

PDFEdit provides easy access to PDF page contents. PDFEdit is meant to be used with the Acrobat PD layer and Cos layer methods for manipulating PDF documents. To use PDFEdit effectively, you should be familiar with PDF page marking operators and the PD layer of the core API.

The PDFEdit layer is sufficiently strong to allow access to edit all of the elements of page content.