That the author suggests that, since the iPad has a landscape homescreen, this could just be enabled for iPhone shows a lack of appreciation of Apple's design sensibilities that pervades this article. Just because the iPad has it doesn't mean it doesn't need designing for the iPhone.
Furthermore, the iPhone is primarily a portrait device. The iPad, not fitting easily in one hand, is as much a landscape device as it is a portrait one. I'd be surprised if Apple "enabled" a landscape home screen for iPhone in iOS 5.