Like most anime movies based on a series, the setting is in an isolated movie-only situation. There are some new people who show up in the movie to be relevant (with a shoehorned backstory to justify that), there's villains to be worried about, and it's up to our heroes to save the day. This formula is followed by this movie to a T. To add insult to injury, only a certain and very small portion of the UA cast were selected to take center stage, while the rest were given 5 to 10 seconds of screentime before pushing them out of the picture once their existence in the movie was established.
To say nothing of the MHA characters, some of them were turned into cliche stereotypes of themselves, while most of them barely did anything to make an impact throughout the movie. And again, this was because of the 95% being cut out of the plot.
As for the movie-only characters, the Shields (which I daresay is a blatant Marvel reference), their part to play in All Might's making as the greatest hero of all time doesn't have the kind of impact the screenwriter must have been banking on. Nothing was at stake or gained with this family; whatever reasons they had for doing what they did or what they wanted to do, were half-hearted and barely believable to really make fans care about what they may achieve outside of the main story, let alone root for their success. The Shields went through the motions of being heartwarming and stirring up the conflict necessary to give them all an adversary to fight back, and they still pale in comparison to the accomplishments of Horikoshi's own characters, who were always a cut above the usual anime tropes.
Nothing was gained or reaffirmed in this movie. It was pure filler from start to finish. On a more personal note, I'm still waiting for Bones (or preferably Horikoshi himself) to write up a movie storyline that plays out like a DC animated film instead of another anime cashgrab, really give me something to get hyped up about.
