I think it would be great if there were a wordpress command line interface for upgrading core, plugins, and themes, and possibly doing other stuff.
As of now, it's impossible to do upgrades on a cron job. That may or may not be a good idea, but I would like the option.
I help manage (and keep up to date) about 60 separate wordpress sites hosted on a couple of servers. Right now we're using a custom setup involving git to update the core, but updating plugins is a nightmare, especially since there are permissions issues (we don't want all files to be owned by the web user, and we don't want to put linux login credentials in a web form). If I go run something like:
php cli.php upgrade_all_plugins
And have it download and upgrade all plugins (like the web interface's auto-upgrade feature), this would be amazing. Anyone else with me?
Drupal has something similar to this called drush: http://drush.ws/
I've briefly looked through the auto-upgrade code and it seems like a nest of authentication/view code along with the actual upgrading code, so I don't know how easy it would be to separate it so it could be DRY. But I'd be happy to help.