Not really so much as before. Because of a new major difference. Microsoft is now linking the DirectX version to the operating system. So the new Xbox is expected to run a similar version of DirectX 11.1x that only Windows 8 is running.
True, while new GPU's can and will get more powerful, the differences will be less noticeable than today. Currently we have the Xbox 360 running DirectX 9c while the best GPU are in a different way all together at DirectX 11.1. It noticeable handles scaling, detail and textures much better. You can see it in this demo, look at things like the texture of the rope, tiles on the room, the stones of the wall and sidewalk. In DirectX 11 they all have extra textures. They also increase in detail as you get closer.
http://www.youtube.com/watch?v=YiS6kzXQchk
The next major graphics update will wait until Windows 9 and probably DirectX 12. Then you will see a graphics improvement, which probably need new new hardware not available today.
In the meantime, it would seem the new and more powerful GPU will allow a better frame rate, and large monitors and scaling across monitors, but not the major difference we are used to seeing in the last 5 years or so.







