How about a feature to enable automatic download of subtitles for videos in the library, which do not have any?
Sometimes, primarily when traveling, I find myself without subtitles for new videos, for which I have forgotten to download subtitles, or for which subtitles would not be required under less noisy conditions. Often this happens when airborne and without Internet connection. It would be great to have a set of subtitles available for offline use automatically.
A feature like this should allow setting preferred language, and possible a secondary and third language priority too.
Allow the user to select whether the download should only occur for videos with no already downloaded subtitle data, or if more of a (one-way) sync should be run downloading new or updated files for all videos where applicable.
A feature like this would also benefit from an option to purge downloaded subtitles, either all subtitle data across the library or only for particular show/series.