Playlist: import only the files that are not yet present, to avoid duplications.
You can select all the files in a folder and import. But when you add a lot of files to a folder and you want to add only those in the playlist it becomes laborious to look for them one by one.
We have released a new feature called Tag Playlists. You assign Media with Tags and then you can create dynamic Playlists using combinations of Media Tags. Then, when you upload a Media, you also add the required Tags, so that they get pulled into the Tag Playlists.
That might work in your case.
In the long run, we are also planning to provide Folder-based Playlists, so that all Media in the specific Folders are automatically included in a Playlist.