Well, of course it's going to be a trilogy.
The profile that The New York Times just ran on Warner's newest CEO, Kevin Tsujihara, was all about the way he's planning to keep Warner in the franchise business in the near future, and one of the things he mentioned was the new project that was announced last year, "Fantastic Beasts And Where To Find Them," an original project by JK Rowling that builds off the world she created for her "Harry Potter" books.
One thing I'll say immediately that makes me like Tsujihara is that he's pushing Warner to produce and release more films instead of less at a time where so many other studios are barely making films. And, sure, many of those films are going to be giant tentpole movies, but that's what allows them to take a chance on something like "Gravity." The "Fantastic Beasts" trilogy will focus on Newt Scamander, a "magizoologist," and it sounds like these are going to be big adventure films that aren't saddled with an overall mythology about someone being The Chosen One and having to fulfill some Grand Destiny. Set seventy years before the "Potter" books, this sounds like it's going to give Rowling a chance to flesh out her magical world in ways that should be an opportunity for all sorts of fun.