It'd be great if user tags and vote totals were included in settings export/import. Losing those would mean dropping Lemmy entirely at this point since I prefer to tag rather than block most problem users. Tag import is also critical if we want to write a script to import user tags from other apps like Sync or Boost (since it'd just be converting one JSON schema to another).
It's a longshot since I'm guessing it'd be incredibly heavy on API calls, but a way to import vote totals from Lemmy's up/downvote history. Voyager's vote tracking is the killer feature that had me drop Boost, but it was weird for the first week or so seeing people I knew I upvote all the time at only +1-3. We can manually set vote totals ourselves so someone could write a script to do most of the work outside of the app (especially if #1 is added), but a native way would be far more convenient.
An option for long pressing the post thumbnail to show an enlarged preview of said thumbnail. Sync has this, if you needed an example of what I'm thinking of.
An option to change what clicking on the OP or community in post view does. It's an incredibly minor annoyance, but sometimes on Android I accidentally tap one of them when attempting to open the post.