I think an amazing feature to add would be the ability to edit posts in listview.
When you're on this link http://www.yourblog.net/wp-admin/edit.php it shows your posts along with date, title, author, categories, tags and status. It would be of use if you could edit the post title, author, categories or tags from this view.
Just my two cents. I constantly find myself wanting to edit tags or the title name and wish i didn't have to open the entire post entry in order to make these simple changes.