You get a few extra millimeters of height and a substantial increase in trackpad width. Substantial changes are limited to the trackpad. The larger cover doesn't result in larger keys or bigger spacing between the keys, the keyboard portion of the cover doesn't really change compared to the previous design. The new Type Cover has a larger surface area, it includes a second magnetic strip for added stability in laptop mode and it's thinner compared to last year's model. Keep in mind though, those old accessories are built for a 10.6" 16:9 Surface but the move to a 12" 3:2 requires a larger cover to completely protect the display. All previous Type and Touch Cover accessories will still work with Surface Pro 3, including features like the backlit keyboard on previous Touch Covers. It seems as if Microsoft came to the same conclusion as Surface Pro 3 is only offered with an optional Type Cover. I could always justify the Touch Cover's existence by saying it was better than typing on glass, but the reality remained that I almost always used a Type Cover with Surface Pro. The Touch Cover always offered the low profile behavior of a traditional tablet cover but it was never all that great as a keyboard. In the first two generations this meant having two different options: a pressure based Touch Cover and a Type Cover with low profile keys that actually move. Along with the integrated kickstand, the Surface tablet was always designed around being used with a detachable keyboard cover.