I'm not mixing Office 2003 documents and Office 2007 documents. In fact I'm working on different installations on different computers.
The whole point is -
When using Office 2003 I can copy and paste drawing objects between applications as expected. Drawing objects remained as Drawing Objects between applications.
When using Office 2007 (only) drawing objects don't copy and paste into Word 2007 (only) as expected.
Generate a number of drawing objects in Excel 2007, select them all and try to paste them into Word 2007. They ONLY paste as an image. There is no option to paste them as Drawing Objects. (Unlike what is available when working in Office 2003.)
Yet you CAN paste the same group of Drawing Objects, as Drawing Objects, into PowerPoint 2007. (The same way you can in Office 2003.)
For that matter, you can draw some objects in PowerPoint 2007, and paste them as drawing objects into Excel 2007. But trying to paste them from PowerPoint 2007 into Word 2007 will only paste into the document as an image.