My opinion, nothing else: The bezel gives you a place to put your thumb when holding the iPad with one hand. A place that won't obscure the screen. Particularly when in landscape mode. A place to brace against the cantilever of the device off your hand. It could have been a little smaller for me, but some have fatter thumbs than I. Find a 1/2" thick book in your house about the same height and width of the iPad and see if you don't have to "hook" a thumb on the top edge when holding it in one hand. Simply balancing on on hand it possible, of course, but it doesn't allow your hand a good grip.
As for icons, Apple could have done much more research and done a better job of making the iPad UI unique and more ergonomic to use. If right handed, the ability to cluster an array of icons on the right side of the screen would have made them all easier to tap with less hand motion. Cloning the iPhone UI was a beginning point for sure.
good point. Even on a cell phone, clustering can make selecting icons more comfortable and quick. Even though both are very small devices, my thumb is not of limitless length!