[siglesias]

Point of correction, Dustin. Navigation Bars are top anchored in iOS. You might be thinking Tab Bars. As such, Tab Bars are being replaced increasingly with Dive Bars, the ones that live under the app, a la Facebook and Path. This makes the reaching problem worse because the common elements are in the top left. I suspect that we might see swipe-based gestures increasingly handle back button behavior and maybe a bottom oriented "under-menu" for placing compose and add elements.

Edit: Appears to have been corrected, but point still stands.