I'd also like to throw my hat in the ring for some beta testing. I've paid up to Now TV until November and was going to cancel but if a better Apple TV app that's integrated with the TV app and Up Next is on the cards I will definitely continue subscribing.
Now Tv has great content, its just a really frustrating app on Apple TV, expecially when there is so much other great content on the terrestrial apps & Amazon, all working with the TV app.
Heads up all you tv Gen.4 & tv 4K owners!
Register now to join a trial of NOW TV's re-vamped app for tv as per the following post...