Brye Kobayashi concepted a different way to implement fast camera access via the iOS Lock Screen. I think his idea could work, though I am sure Apple tested this method before landing on what we see in iOS 5.1. For what it’s worth, I very much like the Lock screen’s new way of granting fast camera access.
As an aside, what’s interesting to me is the way Apple has been innovating the Lock screen while seemingly leaving the Home screen in the dark ages. Depending on how you manage your notifications, the Lock screen could potentially show and give you access to more info than your Home screen: recent emails; recent tweets; the current time, date, and day; recent text messages; upcoming events; sports scores; and more. Also giving you one-swipe access to the apps showing that current data.
The Home screen however still just shows static icons and folders that seem to be in constant need of adjusting and reorganization.