i think it provides a clearer view of the desktop. which is why the iphone doesn't have custom wallpaper on the springboard. it would look too busy.
I agree that this is most likely what Apple is thinking.
I think the "gap" problem is mainly caused by our experience from the iPhone. If there was no iPhone, we would not be having this conversation.
Having said that, IMO both the iPhone and the iPad should have a much smarter app organisation system than presently exists. The multi-page flat icon grid structure we have now is just simply lame. Apple have chosen simplicity over usability. I guess this mimics the form over function design philosophy in hardware.
A better approach would be a hierarchical system, where you can organise, say games, productivity apps etc in folders or whatever you want to call them. But even that is old-school. I'm sure some smart people could think of a way cool new interface that incorporates advanced jestures? How about that each of the "folders" are actually floating bubbles, and you can flick them around and expand them to reveal icons like the photo galleries on the iPad, so you don't have to fully open them to see what's inside... etc