Alien3
Its kind of the poster child for “development hell” There is a good film in there somewhere, but definitely not up on the screen.
I think the chances of a film being any good are inversely proportion to the number of writers involved raised to the power of the number of directors who have been linked to the “project”
I’ve often thought that the Alien ‘character’ / formula is so good, it’s one of those thing it seems almost impossible to make a bad film from, but somehow it’s had a lot more misses than hits.
Development Hell as you say certainly is a part of it, and ‘too many cooks’. I doubt that there will ever be another good Alien film. It’s actually a great franchise for a reboot as the ‘star’ is the Monster, not the Human characters per-se, as good as Ripley was.
What it needs though is restraint, the Xenomorph is scariest when it’s shown in shadow, hidden in the sort organic/technology hybrid claustrophobic environment it builds, not when it’s running around in broad daylight.