One thing that is very difficult on Roll20 right now is clearing out old images from past campaigns. You must go through every single image clicking a checkbox, and bulk erasure by filename and similar are not possible. I think it would be a massive, massive help if users could get direct access to their file library via FTP, so that they could rapidly download, delete, and upload art to the art library in a very efficient manner. I know this would save literally hours setting up some campaigns that use a lot of custom tokens and images and thought it yet another great service to perhaps offer as part of a paid tier.