What should be done to make a modern movie about Frankenstein and yet reasonably faithful to Shelley's book?
I think that the project has to be independently driven. The Hollywood system of producing films that generate profit as the primary motive will not work with Shelley's novel. The text is too intricate and filled with so many deliberate intellectual themes that the Hollywood studio system would reduce it to the most singular element: The monster. It has already done this as nearly ever film version places its focus here. It is in this where I think that control of the project has to leave the Hollywood studios and enter the realm of independent film.
A script writer who really knows Shelley's text also has to be embraced as part of the project. The writer has to be able to see the text as part of something larger. The themes in the work apply to both Victor and the creation. A faithful film version has to develop both sets of characters. At the same time, being able to show the monster with consciousness, making him a pitiable figure and making Victor a flawed one are essential to ensuring that Shelley's text is reasonably respected. Being able to make sure that the themes and characterizations are essential to the process of assembling a film about the work is one of the first steps to ensuring that Shelley's ideas are treated with respect and shown reasonable faith.