Adam C. Zern discusses a few ideas about why Brandon Sanderson's Mistborn should be adapted into a film:
"Being a lover of books and movies I naturally visualize in great detail what the events, environments, and characters of a particular book would look like if they were put to screen. Mistborn by Brandon Sanderson was a book I found incredibly easy to envision as a film and hope that one day an ambitious enough filmmaker with a big enough budget could adapt it for movie-going audiences.
To begin with, what Mistborn has in ready abundance is compelling visuals. Although the book presents a dying world, including persistently falling ash, the images possible could be extremely haunting but beautiful. It's a built in symbol that could be easily exploited by an adroit filmmaker. Furthermore, Mistborn's mystical magnetism, which is at the heart of its fantasy, provides innumerable opportunities to showcase the type of action sequences modern audiences thrive on. The film could easily transition between being exceptionally brutal and stunningly elegant in its violence. A talented production designer, costume and make-up artists, and special effects guys could work wonders with the city of Luthadel, the terrifying Steel Inquisitors, and characters like Kelsier and Lord Ruler.
Leaving visuals aside, however, Mistborn could be a wonderfully entertaining film if its main character, Vin, were appropriately portrayed. When Vin is first introduced to the reader she is timid and abused, but eventually becomes, under the tutelage of Kelsier and his partners, a formidable warrior and heroic personality. The fact she is a female makes this possibility all the more interesting. If the filmmakers were to cast a very capable actress like Saoirse Ronan the character could easily endear the feelings of the movie-going audience. Also, the camaraderie existing among Kelsier's crew could create a powerfully emotional dynamic in which audiences could willingly become invested in. At the end of the day, if a film doesn't have characters worth watching no amount of visual style can salvage it.
A book like Mistborn is filled with interesting ideas and interesting people. Some of those ideas and characters may need more development and might take a little more attention to find than others, but an apt screenwriter would have no problem culling the most important elements. Mistborn is not exactly the A Tale of Two Cities of fantasy books, but decent movies have been made from far inferior books (think Jaws). I think Mistborn is ripe for the adaptive picking and hope that one day someone takes a chance."