That is indeed a dramatic change for the iPad. While it stills keeps the same screen size and general shape, the iPad went from 13.4mm to 8.8mm thin. Yes, it’s even thinner than your iPhone 4!
Not only it is thinner, but it is also lighter as it went from 1.5 pound to 1.3 pound. Not a huge difference but it’s still going be easier for you to handle.