Allow sorting by frequency and also by number of unplayed episodes
These are different ideas:
Sorting by frequency would allow me to prioritize episodes which are published daily over those which are published weekly, for example. We can already more or less do this via priority, but not quite. This would allow me to hear low frequency podcasts immediately, which otherwise tend to be burried in long playlists.
Sorting by unplayed episodes already works on the subscription tab, but not on the playlist. This would allow me to prioritize episodes from podcasts which have a lot of unplayed ones, thus allowing me to catch up or binge listen a particular podcast, but to do so integrated into a playlist, and thus have other podcasts in the middle, for variety's sake if for nothing else.