Development Hell: The tale of Alien³'s development is the stuff of industry legend, and a prime example of Executive Meddling in full force. A rotating lineup of directors who all got shunted aside by FOX, delays, reshoots, disastrous test screenings, tensions between FOX and (then-newbie) director David Fincher, a "pay-or-play" deal between the studio and Sigourney Weaver, Fincher getting locked out of the editing room, executives and writers at odds as to how the story would play out, months spent building sets that had to be shoehorned into a completely different script...it all added to a giant mess in its development.
Executive Meddling: By the time David Fincher was officially signed on to direct, the film had already gone though a dozen or so different writers and directors, and almost two million dollars worth of sets that had been constructed. With the release date looming, the studio had Fincher begin filming -without even a finished script in place- ordering him to essentially make up the plot of the film as he went along by piecing together parts of the other unfinished scripts and improvising the rest. The studio constantly demanded reshoots and rewrites throughout the films production, and often blocked Fincher from filming key scenes (some of which he filmed anyway and made it into the final cut). When it finally came around to editing, the studio ordered that radical edits and reshoots take place in order to shorten the films runtime by 30 minutes, causing Fincher to become infuriated and walk off set. David Fincher has since ended up disowning the film because of his horrible experience working on the project.
Old Shame: David Fincher doesn't list Alien³ on his resume and refused to record any interviews or commentary for the Quadrilogy box set, due to lingering anger over the Executive Meddling during production.
Troubled Production: One could probably do an entire semester of film school class on the problems Alien³ faced:
Directors and writers kept getting hired and fired during pre-production because the studio couldn't decide what direction they wanted to take the story in,
Shooting began before there was a finished script,
Sets which had already been partially constructed when filming began had to be rebuilt or worked around,
The production was $7 million in the hole on the first day of filming,
And in the end the studio wound up editing the film into an almost unrecognizable mess.
What Could Have Been: Alien 3 went through several writers, including William Gibson, Eric Red, David Twohy (who would later use some of the script he had written for Pitch Black) and Vincent Ward, before the final shooting script was thrown together using parts of all the previous drafts (mainly the latter three). Summaries of each can be found at The Other Wiki. For interested parties, the full version of Gibson's draft can be found here. Gibson notes that the only part of his script that made it into the final film was his use of the Scannable Man trope.