Features wise, full mod tools would be awesome, but I figure you've got that on the list already. Same with the latest lemmy stuff like instance blocking at the account level.

Beyond that, the only thing I can think of is more granular control over theming. I finally found a set-up that's working for me, but I know it took some fiddling that could have taken less time if I had been able to tweak background colors, or whatever. I've seen other people talk about that for sync, as well as other apps that a don't even have the options sync does. From a usability perspective, contrast between sections of the ui can be the difference between literal headaches and a relaxing scroll.

But, again, that's pretty low priority imo.