Blade Runner is interesting as there are 3 different versions, all about the same length but with some very different scenes. Theatrical also has a terrible voice over which was later removed.
The Shining is one that gets better when shortened - most feel that the 119 minute European version is better than the 144 minute US cut.
Apocalypse Now is interesting - Redux (193 minute) is a slog compared to theatrical (147); but Final (182) is probably the best version and a great example of the balance needed.
There's also the video 'How Star Wars was saved in the edit' which has a lot of good information on what editing can do. The video has kindof been co-opted by the internet as definitive proof that George Lucas is a talentless hack, but it's really not that much different than what happens on every other film. https://www.youtube.com/watch?v=zEHRNS-Scrs
For me the opening scene added in the extended edition of Aliens completely ruins the first half of the film for me. Sometimes less is more...
https://www.youtube.com/watch?v=GFMyMxMYDNk&ab_channel=Rocke...
Gallo eventually went back into the editing room, and emerged with a new version of the movie. Ebert watched this new version, and afterwards was quoted as saying "It is said that editing is the soul of the cinema; in the case of "The Brown Bunny," it is its salvation."
Source- https://www.rogerebert.com/reviews/the-brown-bunny-2004
Gallo fought back, insulting Ebert for being overweight and even, strangely, put a curse on his colon. Ebert adeptly responded, "It is true that I am fat, but one day I will be thin, and he will still be the director of 'The Brown Bunny.'
There are a lot of things that a production can't recover from, no matter which other elements are excellent:
* Bad director
* Bad cast
* Bad writing
Get those 3 things right, and you can recover from bad special effects, bad costumes, bad make-up... even lousy cinematography or low budgets.
If an actor gives a committed performance while filming, they could have the sense that it is either amazingly good or amazingly bad. And either premonition could be right or could be wrong.
(Not to get into what makes something "bad" anyway which is a whole 'nother subject...)