Sounds like a good idea.
For the time being, here's a workaround: Open the photoscan .psz files with a zip software (rename to .zip before), extract the files (use different directories to avoid creating a big mess), open that doc.xml files in an editor, copy the section that defines the bounding box (the stuff within the <region> [...] </region> bracket) from one to the other file, save the doc.xml, zip the files in each directory, rename to .psz, open in Photoscan. Easy, isn't it? ;-)