For one thing, the original intent was for each of the three flicks (read: adventures) to be very brief, presenting them as outlines rather than full adventures. As the first flick progressed, it became clear that it deserved the full treatment rather than a glossed-over adventure seed. The flick ended up being much larger than the original projection.
Also, we like to ensure that our products are thoroughly playtested and the second and third flicks haven't been afforded that opportunity yet. The first flick has been playtested numerous times, long before a single word of the supplement had been written.
The entire trilogy will be vastly superior as a result of this revised formatting. We hope you understand.