I was also bothered by it not recognizing the view-source: prefix to show the source of any URL until I found the Activity window. The Activity window shows all the URLs loaded with a particular page and you can double-click them to view them individually. Nice. Still, the View Source bookmarklet has worked in basically every browser for years so it would be nice to support.
I found a site describing a Safari Enhancer that “enables several hidden features of the Safari webbrowser beta.” The screenshots show a Debug menu with a View DOM tree item, the ability to change the browser identity of Safari, a minimum font size option, and ways to import bookmarks in various formats. Sounds helpful. Too bad I don’t have a mac to play with all the time.