As often discussed here (a few links below), the Media Library is one of the biggest pain-points on Prismic.
I find all the content editors I work with completely ignoring the Media Library, and instead keeping the files organised locally on the computer. They re-upload images to Prismic each time, even if the same image already exists on Prismic, meaning the same file might eventually need to be downloaded multiple times on websites as well.
They all wish to have, and typically have tried, to drag & drop the file directly on the image field itself without needing to open the Media Library in the first place.
I would love to see it working this way, and can immediately see the improvements in the content managing experience. Obviously the Media Library could still exist just as before, allowing users to pick images from there as well.
As a bonus, in order to avoid the same image being uploaded multiple times, behind the scenes Prismic could check if the image has already been uploaded and automatically link to that instead of the uploaded one.