The option to separate file and folder permissions for a specific folder tree.
We have a folder structure that we use for our external partners where each external entity has their own subfolder. Our internal user community needs Editor permission to manage the files – move, delete, and rename but that gives them the ability to accidentally drag one external partner’s folder into a direct competitor’s folder. This would be a disaster. If I could give our internal users File-Editor and Folder-Viewer Uploader permissions the likelihood of the above mistake would drop significantly.