Thanks for working on this!
I would have thought the size would be reduced by more than that.
Did you verify that your script actually got rid of all the non English .resx files, ie files that end with .**.resx rather than just .resx from App_GlobalResources?
and from the /Data/HelpFiles and /Data/MessageTemplates folders?
If your script works and does remove the files I'd be glad to test it and make it available to others as a download.