That's a good thing, right?
Yes and no. Because of this, the outlet adds, Xbox 360 discs won't be able to run on the Xbox 720, which basically rules out the hope of hardware-based backwards compatibility. Might there be a workaround for this? Sure, but even still, it is a little disheartening.
Microsoft is expected to unveil the new console next month on May 21st, so hopefully all (or at least most) of our questions will be answered at that time.