It would be great to have page up/down buttons implemented on universal remotes when browsing through the guide or in lists of recordings. This feature is already available on the Android TV version of the app, and it's the thing I miss most since switching to the Apple TV.
Hopefully this can be implemented, as the page up/down buttons already work when watching a recording (they skip back and forth through the ad break markers), so the Apple TV and Channels are definitely capable of receiving and reacting to these commands.