I think that feature is the disruptive angle to the AppleTV and that's the reason I bought one. Here's why:
All Apple has to do is add a single Boolean switch to the built in video player: allowsAirPlay. If they do this, then with a single line of code, any app developer can make an app that allows their content to be streamed to an AppleTV. Your iDevice becomes the worlds most powerful remote control almost instantly. Developers (studios, individual shows, whatever) just need to create apps for iOS which authenticate or manage the subscription to their content, and the customers can tap a single button to see it on their big screen. You gain all the advantages of apps on the AppleTV itself without actually needing them to be installed there!
Suddenly the App Store becomes a cable TV network. The added benefit is - you don't need to have an AppleTV to enjoy the benefits! Plug your iPad into your TV using that adapter cable, and you could still enjoy the same content. Or take it with you when you travel - your TV channels are all there. And when you're at home, just tap the AirPlay button to see it on the big screen.
That's the disruption I'm hoping for and Apple has every single piece in place now to do this.