The hardware has not changed since it was demoed 4 years ago (outside of a slightly larger 120gb hard drive). The software has seen some nice updates, 3x.
The hardware needs the most attention, and it seems it will finally get it, along with iOS.
Other than hard drive size (40 GB and 160 GB), the hardware never changed. When AppleTV 2 was announced, there were a lot of people under the impression that the hardware was changing, but they were mistaken. All updates were software only (once again, other than adding the second HD option).