Firm up the foundationals: proper parsing of complex formatting (e.g. a bolded section within an italic section), which reminds me: enabling a Preview ability for comment replies to posts not just to existing comments. Also, the former might have already been done though I definitely recall instances in the past where it did not work.
Clean up notifications: e.g. if a post is deleted after you receive a notification about it, then either delete the notification also or at least let us see the post - it's super annoying to have a notification that goes nowhere.
Also, notification links should always actually go to the things they point at. On some posts the comments are now loading separately for some reason (perhaps if there's a lot of them? but even then why not load them at page start rather than delay?), which breaks the Notification links. Many things break those notification links actually. Another one is people from instances that you have blocked - you can't see the comment that the link tries to take you to anyway, so what use is the notification at that point? Either remove the latter or... something, maybe show the comment after all in that special case (except wait no, if you blocked everyone from an instance then likely you did so for a reason, and do not want notifications from them?).
Edit: here is an example link, where it looks like the Continue thread breaks the link to go where it needs to on the page.
These kinds of "polish" features that are still lacking are annoying and I for one would love to see them worked on, before adding all kinds of other features that I'll likely never use - whereas typing out comments and viewing notifications are the top 1/2 of all things that I do on PieFed (besides look at posts and vote on them:-P) so these would highly benefit from being polished! 😄
Though I still love PieFed even while having to wait for them too. 😊