The new UI is temporary just like the previous ones have been. There have been at least 3 major redesigns of the UI so far. They change as needed to introduce n

The new UI is temporary just like the previous ones have been. There have been at least 3 major redesigns of the UI so far. They change as needed to introduce new features. The current design is to make room for third party content & services. In this sense the current generation Apple TV is just a place-holder for a future product. Apple has said as much by referring to it as a hobby. What they are doing is laying the groundwork for this future product. AirPlay, iOS Remote, 1080P video, third party services with sign-up and payment, iCloud, etc. The current generation Apple TV is almost just a public beta test of these technologies. When they are ready to do the 'real' Apple TV they will introduce an entirely new UI to go with it. This sort of public R&D isn't what Apple normally does but I think the challenge of building this product requires it. They need to soften the ground a bit. Of course other companies are working on the same things which helps too. People are comfortable with IPTV services. Current residential broadband can keep up fairly well with good 1080P video. The more SmartPhones and tablets sold the closer we are to ditching a dinky multi-button remote control in favor of multi-touch control. The integration with the cloud for re-downloading content and interconnecting different devices solves a ton of usability problems. Step by step each one of these changes are laying the groundwork for something bigger.