I would like to be able to specify default values for several of the parameters that control imagedata sizing for print|FO|PDF output. For example, if I always want every imagedata item to proportionally scale to the maximum viewport, it would be nice if I could provide default values for scalefit, width, and depth, &c.
When needed, these could be overrided within the individual imagedata elements.
The motivation for this is that I find that in the vast majority of cases, I want my images to be as large as they can be on a page. It's much less common for me to provide a specific scale to an imagedata element. Currently, my options include touching every imagedata element by hand -- or by preprocessing XSLT -- or by manipulating process.image.