I absolutely love the Channels app allowing me to use my Apple TV as the one device, but a great update would be implementing Freeview Play.
Most smart TVs in the UK are now coming pre-installed with Freeview Play, allowing the user to use the EPG to go back in time and watch a show, connecting via a catchup service. This is quite a seamless experience and would be a great addition. Especially if Channels cannot be integrated with the TV App, this would replicate some of the functionality.