Favorites add/remove are now accessible if you go to Search under TV Shows/Itunes. Search for the show you want to add or remove. Once you've found it, you should see 3 or 4 buttons under the description, such as "Play".... The last button should be "+ Favorites" or "- Favorites".
It just took me about an hour to see this, as I was incorrectly searching for the Favorites options under Purchased like on Gen. 3.