I noticed this morning that the main World of Warcraft site is indeed raw XML styled with XSLT. They’re serving straight XML directly to browsers. It appears to be mostly well-formed HTML (but not XHTML) wrapped up inside a custom page element.
I’m not quite sure why they’re doing this. It seems like an extra burden just for a different root element, but maybe the stylesheet does a little more. Hmm, looks like they’re using XSLT as a client-side templating language. Not bad. Saves them bandwidth and server-side processing I expect.
Interestingly the HTML includes some JavaScript. JavaScript inside XML didn’t used to work, even after a transformation to HTML. I’m guessing at least some browsers have gotten smarter about that.