Show the podcast episode subtitle (ATP has them, not sure about others).
Allow search of all episodes across all subscribed podcasts (title/description).
Allow search of all episodes across all podcasts, even if not subscribed (title/description).
Option to manually sort subscribed podcasts in Library.
Similar to above, an option to organize subscribed podcasts in Library into sections based on new episode action (queue next, queue last, inbox, nothing). This shows users how new episodes behave without them having to check settings. It also groups and showcases podcasts using action as a proxy for importance, i.e. queue next being most important.
When unsubscribing from a podcast, a prompt should ask whether or not to remove its episodes from the Queue and Inbox. I often want to unsubscribe from a podcast and keep its episodes in my queue. Right now, I either have to wait until I've listened to the episodes before unsubscribing or recreate my queue after unsubscribing. This could possibly be a toggle option in settings.
A toggle switch in the "Downloads" settings called "Download Inbox Episodes" that enables auto-downloading of episodes as soon as they're added to the Inbox. I like to leave episodes in the Inbox to keep them organized by podcast and in chronological order but I wish they would download and stay downloaded without ever having to queue them.
A podcast info view that shows the distribution of episode runtimes, the average length of time between episodes, and other easy-to-calculate stats for a given podcast. Would be useful for vetting new podcasts.
Ability to create multi-podcasts. These would show in the Library like any other podcast but would be a combination feed of multiple podcasts, similar to a multireddit. For example, I would like if I could combine all of my favorite film review podcasts into a single feed that I could then browse and search. A multi-podcast could also be set up to show the feeds for an entire podcast network. Multi-podcasts would only be visible to the user who creates them, since it's not actually creating a podcast. It would just aggregate multiple RSS feeds locally on device, similar to a playlist.