So far, the new Twenty Twelve theme is not much to look at. It has it’s basic form, but nothing fancy has been added.
This is not yet a fully working theme—we’ll be adding in more features and lots of missing styles over the next 3–4 weeks. Including post formats, comments, archives and page templates, more in-post styling, and a nav menu rework so the main content comes ahead of the navigation.
…says Lance Willet, who is a member of the team building the Twenty Twelve theme.
Something to remember is that the WordPress team committed to developing a new theme every year. The WordPress project had a history of keeping around an ole and stale theme, Kubrick for example. While it was a great theme, it became quite annoying to see so many sites running it.
We should not expect anymore updates for Twenty Twelve until late this month.