I agree with the PP that your own tastes and wants should dictate what you try to book. I think too often we see posts from people that say something like this: "I finally got a reservation for Be Our Guest after trying for months, but now I look at the menu and there's nothing I like. Should I cancel it?" Posts like that beg the question, why try for a reservation without at least knowing whether the restaurant has food you would like? And it shows that some people are so focused on "what are the popular, hard to get, ADRs" instead of "what would I like".
That said, some of the hardest ADRs to get are for Be Our Guest, Ohana, and Cinderella's Royal Table. The new Rivers of Light dining package and the new character breakfast at Trattoria al Forno with Rapunzel, Flynn, Ariel, and Prince Eric will likely be difficult ADRs to get as well. But if there's any restaurant you want to eat at, or a specific day and time you are looking at eating somewhere, book it as soon as your window opens rather than waiting. With as quickly as ADRs get booked up, waiting to book will limit the choices available to you.