The writing is on the wall that a movie would be a disappointment. I can see a multi-episode animated series in the animation style of Arcane or Castlevania: Nocturne. But the story has so much character development, especially with main characters, such as Vin and Kelsier, that there's no way a movie would be able to capture it along with developing the world of Allomancy in an interesting or meaningful way. A good portion or all potentially all of it would be sacrificed in a movie script.