I think it'd be nice to use HTML5 semantic tags like nav, header, article, aside, etc. where it makes sense. Of course, not every div should have semantic tags, but having the main parts of the site semantically tagged might improve the SEO of our sites and make them more usable for impaired people.
But I'm not sure whether a theme can do this or it depends or Wordpress itself… Sorry if I'm wrong and should be posting this into WP forums.












