Near as I can tell the bezel is the exact same width as the iphone/ipod touch.
I suspect it has to do with them playing wide-screen with the iphone and figuring that given the ipad will likely be rotated they just put it all the way around.
also for those who are saying the iphone/touch doesn't have a wide bezel for your thumbs why does the iPad need it?? well you can hold onto all 4 sides of the iphone/touch with ONE hand, which one can't do with the iPad. Well unless you have really really big hands