Like the iPod itself, it's not a question of new functionality, but better usability/popularity of existing functionality. The revolutionary aspect was that you could just drop an iPod into the dock and it would start playing your music through the dock's speakers, while also charging. This didn't require the dock to be "smart", it was analog audio.
Apple's marketing is working a bit too well.
Moving the audio to all-digital moves more NRE cost to the devices. It also means there's a potential for the "choice" of rubbish DACs to save cost.
Not smart, just have a 30pin connector. Having DAC on board would be trivial (esp. after paying the royalties for the connector). So calling it revolutionary is just being an Apple shill.
