I'm planning to add an XML Sitemap to a client's existing website. According to this, it will help define the difference between the root website (aimed at UK) and the US website (aimed at the United States) and a few other languages/locales.
Is it enough to add only this to the sitemap or will Google punish me for not adding all pages in there? The content changes quite often and we don't have a way to deal with updating the XML regularly at this point. Also the existing content is well indexed on Google already, it's just the concern about multiple pages in English that's behind this.