Hello LJDawson, let me start with saying how happy I am to have Sync back :)
The one issue I have with Lemmy is duplicated posts between different communities (see screenshot). Posts usually have same title, author and link, yet differ in community/server they are posted to. It would be great to be able to make the appear as one item on the feed with some note below that links to both instances' posts, or something like that basically to make them not appear twice or thrice one under another.
Have the various comment threads on a carousel once you click in. Because of the fractured nature of Lemmy servers I feel like I see way more reposts than on Reddit. It would be nice for them to get merged in some way.