I'm using the app for Roku right now, have not tried my Apple TV yet so this is all relevant to Roku only. The features that are needed are as follows:
Favorite a channel in the guide
direct tune to a channel
if you move too fast through the guide it freezes and you have to back out of the app entirely, there needs to be a 'refresh'
More sorting options, sometimes i want to sort by name of program since i know what i'm looking for just don't know the channel, likewise need more sorting options overall
Please let me know if i just simply overlooked a feature and posted it above. Thanks.