The previous version of the WordPress theme uploader checked the themes against the theme review guidelines, but only reported the first error that it encountered, sometimes trapping theme developers in a frustrating cycle of trial and error. The new version performs an even more intensive scan of the theme and returns a list of all results, providing theme developers with a handy to-do list to get their themes up to spec for the directory.
Have you submitted a theme with the new uploader yet? Does it help to streamline the process? If you haven’t uploaded your themes to the official directory, does the new uploader inspire you to give it a try?