Code to text ratio was long conciderd to be a real SEO messurment, but that has started to change. Nowdays its more conciderd as an interresting detail.
Google and other searchengines has pointed out that the ratio does not really matter. But what does matter is that Google and your users need to know what the page is all about. If the site contains several megabytes of images of cats and dogs but no real text at all, then google might not really know what the page is about. Thats a good reason to keep track of a webpage to validate that there is enough text on every page to make sure the searchengines knows what its all about.