Wow, what a bizarre project. I'm not saying they can't pull it off, but a few concerns immediately come to mind:
(1) The Burton movie is not well-liked, and one of the major changes they made was to give Wonka a backstory. I personally don't mind it, but I can see an argument that giving him a backstory ruins some of the mystery and charm surrounding his character. Burton aside, prequels in Hollywood are dangerous territory where quality is concerned: they invite all kinds of lazy attempts at fan service, trying to answer questions that nobody asked or cares about, making for incredibly grating experiences.
(2) I have become less and less enamored with Chalamet the more things I see him in. I don't think he has much range, and this will be the biggest stretch for him yet.
(3) Curious to see how they handle the Oompa Loompas, considering they have not aged well as a story device. It's easier to write it off when it's just a part of the whimsical nonsense world of Wonka's factory - but trying to actually incorporate it into a hard backstory? It may come off very badly. We'll see if they try to re-frame it through a modern lens to make it less problematic.