Have you tried to save a file to iCloud Drive on your iPad? The experience is horrible, because all of the folders are expanded. If you have lots of files and folders in there, it's basically impossible to navigate to the location you're trying to find. Apple should add an ability to expand/collapse folders, and they should all be collapsed by default. The addition of the Files app is a great step in the right direction, and the drag and drop file management is also awesome. But without this update, File management on iOS will continue to be pretty limited I think. If you're an iPad user, and you plan to use Files a lot, it's definitely worthwhile to request this feature through the Feedback app!