Dear Robin, could you explain what LaTeX Watch does over an above latexmk? If the main idea is as you describe it in your initial post to the mailing list:
The idea is that you can 'watch' a LaTeX document, so that whenever you save a change the display is updated as quickly as possible to reflect the change.
then this can already be achieved with latexmk with the -pvc switch. If the LaTeX bundle could be modified to pass arguments to latexmk (which it already partially supports) then none of this code is necessary. Just a thought. Best, Mark