Oh, good grief.
It's doing a lot right. It's built on the Mirai-Mofurun relationship, although they haven't forgotten Mirai-Riko. Mofurun becomes a PreCure, which would have been gobsmacking if the movie's title hadn't been a spoiler. It has good jokes. I enjoyed it when I first watched it, two years ago.
Today, though, I struggled to keep my attention on it. The film was released on 29 October, between ep.38 and ep39 of the TV series... so, whoops, it's second-half Mahoutsukai. Oh dear. The girls are anti-drama. They're sweet and likeable, but they're smothering story momentum. I hope that's just me and that normal people enjoyed this, but even so I can't give this a recommendation.
It has fantastic trailers, mind you. The girls visit a land of teddy bears and fight a villainous one. You have no idea how cool that looks. Mofurun (i.e. Mirai's talking teddy bear) is the film's best and most important character, befriending the baddie, being awesome in a fight scene ("it's important, mofu!") and donating her wish to her friends. Natsuki was impressed by her action scene.
She also has a pseudo-death that plays like a dry run for the tear-jerking scene in ep.49.
Sometimes, the film came alive and even made me laugh. The bad breath stink bombs are funny. Mirai, Riko and Haa-chan are nice. (Of course.) The baddie's emotional journey is predictable, but still pleasing. Mind you, everyone running away from his magic powers in the past was dumb.
Oh, and it's not really an action movie. That's okay, but it isn't. If you want a non-token number of fight scenes, watch the Mahoutsukai All Stars movie instead of this. Incidentally, those Miracle Lights look like dildos.
If I rewatch this film in five years, having carefully avoided the TV episodes, I'll probably enjoy it again. Theoretically, it's got everything. Character moments, jokes, a light touch, an emotional journey for the antagonist, a unique story role for Mofurun... but it didn't work for me. I kept getting pushed out. Mirai, Riko and Haa-chan have become drama-killers. I'd enjoy the good bits and acknowledge that a particular scene had been well done, but it wouldn't hook me. The film never built that dramatic momentum that keeps you watching. I'd drift away. That's probably not all the film's fault, though, and I'm crushing it under the weight of fifty TV episodes.
It's kind-hearted and sweet. You'd have no qualms about leaving small children in front of it. It's a bit underplotted, but less so than some other single-team PreCure movies around then. None of that was my problem with it.