I haven't touched the Frankenstein fandom in a while, so I wanted to share how I personally would interpret Frankenstein into a film (not saying Guillermo Del Toro's was bad, I just didn't like how it was so different from the book)
1. Make it a short tv show!
A book like Frankenstein has a lot of complicated parts, and likes to over-explain itself, which is a perfect fit for a tv show with maybe 8 episodes.
I feel like a lot of us saw romantic tension between Henry Clerval and Viktor in the book, so I want to be able to explore that, I love a queer historic romance.
I want to keep her extremely similar to the book, so the traits we are given, I'll amplify (her motherly personality, her love of her country and the landscapes, ect) and I would give her hobbies that are touched on in the show, it mentions in the book her love of her countries landscape (like said above) so I might make her interested in painting, and I think it mentions her love for poetry, so I might make her read/write poetry!
4. Viktor and Elizabeth's dynamic
I wouldn't want to change their dynamic to much from the book, but also remove the incest-y part of it. My idea was to make them love each other like brother and sister, and have Viktor tell Elizabeth he loves Henry, and have them agree to get married to keep Viktor secret. But of course, I would still have them be extremely close.
5. ACTUALLY MAKE VIKTOR 19-20
It always annoys me how in every rendition of Frankenstein, Viktor is always made into this old man, when in the book, he's in collage when he makes the creature! It's also a very important to his character, as it adds to his naivety about what creating life really entails.
6. Give him a healthy relationship with his family/father
Viktors love for his family and father is a very major driving point for his character, so I really want it to show.
7. Make both Viktor and the Creature morally gray
We all love the creature, but I want to show how both Viktor and the creature are very flawed, and have both done horrible things.