20 Things You Didn't Know About Star Wars: Episode IV - A New Hope
14. The Original Script Was Almost 300 Pages Long
In its embryonic stages, George Lucas' early script for Star Wars was between 250-300 pages long, the result of spending a year forming his ideas into a semi-coherent story.
Even when it dawned on Lucas that this would simply be untenable as a feature film, he was extremely reluctant to cut anything out.
And so, he decided instead to split the script into a trilogy, with A New Hope adapting the first third-or-so of that script, amid the hope that he'd get the chance to make two further films in the future.
Obviously everything worked out for the best, though this probably explains why A New Hope is a relatively self-contained story all things considered.