What I find sad is the fact they took 15 episodes, which the creator calls the "first act" of the movie that is supposed to come out. The problem with is, as mentioned, what's the point of having 6-7 hours of a "first act" of a 1.5-2 hour movie?
We haven't seen these characters in five years, which is a pretty big gap to cover. This "first act" is really a recap of what they've all been up to since we've last seen them. Now, a movie won't need to waste time on that.