If they bring in a better notification system and lock screen, that itself would be a good enough reason for me to upgrade to iOS5/iPhone5. The writer's on crack though, if he thinks Apple is going to reverse their decision about sideloading 3rd party apps or integrating Gmail features into the mail client.
At that point, the Apple app store will be so established and prevalent and known to the masses that unless you really needed to, you wouldn't use sideloading: not unlike how Apple app store and the JB app stores exist now, but officially.