- Sony Pictures' involvement in the pre-production stage was confirmed via the Sony email hack, which revealed discussions between executives of Sony and Hasbro over a potential co-financing and distribution deal. However, disputes over creative direction (Sony reportedly wanted the film to take place in real life, where the ponies would interact with humans, much like in The Smurfs), financial and contractual stipulations caused the negotiations to fall apart. Hasbro ended up solely funding the movie through its Allspark Pictures label. Sony did still try to make a distribution deal with Hasbro over the movie, but the hack fallout and executive shuffling that followed led to Sony pulling out of the movie entirely, leading to Lionsgate stepping in to release the movie. Sony's bickering over the script was actually the prime reason Joe Ballarini was hired to help co-write the script with McCarthy. Thankfully for Sony, they did manage to get a piece of the movie's pie, though: Hasbro later commissioned Sony Music label RCA Records to handle the soundtrack.
- While Sony was still attached, there was a whole treatment of the film that originally concerned Twilight and her friends dealing with the return of an evil alicorn named Cosmos, who is implied to be Celestia and Luna's brother, resulting in friction between Twilight and Celestia over the former's capacity to handle the situation. Executives who looked over the treatment complained of severe Continuity Lockout and numerous Plot Holes regarding the characters and setting, which would have resulted in a much more limited audience than desirable. Judging from Meghan McCarthy's assurances that the movie wouldn't play out like an extended TV episode, it would seem the creative team took Sony's push for a more self-contained story to heart (albeit ignoring their suggestion of one set in the real world à la The Smurfs).
- When Liev Schreiber first saw the Storm King's design, he initially interpreted his character as a Tibetan demi-god and gave him an accent to match, which was quickly shut down.
- The Art of My Little Pony: The Movie contains a wealth of rejected character, story, and location concepts. The overall content suggests a much, much Darker and Edgier version of the film, but notes from the creative team show that much of it was deliberately done with the intention of dialing it back down to fit the show's tone.
- Tempest Shadow's current character is an evolution of Cosmos, Celestia's brother and the Big Bad in the original draft. From there, she became a pony with different animal body parts and a prosthetic horn, to one in a monstrous suit of armor that hid her identity, to a rugged survivalist who was more of an anti-hero than a villain.
- The original concept for the Storm King had him as a three-eyed, quadrupedal creature resembling a cross between a dragon and a wolf. He was also more directly connected with storms, in the sense of being interpreted as almost a storm elemental.
- One version of the film's opening would have featured the Storm King stealing his staff from the Arimaspi King, while another would have shown an aged Scorpan as the staff's original owner. A later draft would have revealed his staff to be a fashioned branch from the Tree of Harmony.
- Various subplots, such as a lengthy trek though a massive, alien-looking forest beyond Equestria, to an encounter with an obnoxious "mud trolls" midway through the journey, were cut and/or shortened to condense the story.
- Capper was originally a fox named Mendax, named after the Latin word for "liar", and he had a sentient scorpion's tail that expressed his true motives behind his cheerful facade. He also had a hidden deformity, such as an extra set of eyes or a pair of antennae, which Rarity would help him come to terms with. Besides a cat and fox, the artists also considered other species for Capper, including a black-footed ferret, a Siberian husky, and a honey badger. Another alternative name for him was Tybalt.
- In a concept for Klugetown that even the artists themselves admitted was way too dark, the whole city would have been built around a colossal dragon skeleton that was impaled on a sharp mountain peak, where citizens would mine for its crystal heart. If not for The Journal of the Two Sisters (which is already ambiguously canon), this probably would've given some disturbing implications for the Crystal Empire...
- Captain Celaeno was called Madame Harpy, and she and her crew were straight-up villains who would undergo a HeelFace Turn, rather than just being friendly from the start. In addition, the designers toyed around with making the pirates dogs and monkeys among other things before settling on parrots.
- Princess Skystar had two sisters named Haven Bay and Salina Blue, who became background characters to give Skystar a Friendless Background.
- The artbook mentions the Mane Six and Spike being thrown in jail by the seaponies after their attempt to form an alliance with them goes horribly wrong. Fluttershy would have convinced passing fish to break them out. In the movie, Queen Novo instead uses her magic pearl to transport them to the other side of the sea in their original forms.
- The climax would have featured a Big Damn Heroes moment involving the hippogriffs. Since this would have taken focus away from the Mane Six, it was changed to give them the spotlight.
- There was an idea for the Mane Six to take on Super Modes in the final battle against the Storm King, but the creative team felt it was too similar to the climax of "Twilight's Kingdom" from the series.
- There was meant to be an introductory exposition scene of the four princesses with Twilight as the narrator in the opening, but it got cut from the theatrical release to pad the runtime for the opening logos. The scene in question was made available on iTunes release, however, and was included as a bonus feature on the DVD/Blu-ray.
- There were plans for a sequel to the movie, but the film's disappointing box office take led to it being reworked into the television special My Little Pony: Rainbow Roadtrip.
What Could Have Been / My Little Pony: The Movie (2017)