Since it's no longer possible to access /sdcard/Android/data directory on Android (see MCPE-149447), please add a new feature that allows to export/import Minecraft data to/from another folder on external storage. For example we could go back to old /sdcard/games/minecraft folder or any other folder. Modern Android versions allow apps to access any folder (except /sdcard/Android/data) so both Minecraft and other apps (like file managers) could access this folder.

Now it is understandable that there could be performance issues or other issues with storing game save data outside /sdcard/Android/data all the time, but implementing export/import functionality should be fairly trivial. This will solve all the use cases like backing up or adding resource packs, etc.