Yes, I agree that is a useful idea and many other apps have it (so probably users are accustomed to it). I'll consider it for this week's development cycle, thanks!
p.s. I'll also have a look at how the drawer is populated because the old implementation to have "favorite on top" is incompatible with community pagination which was introduced later (and since no one was actually using favorites I didn't realize).
Also, it'd be nice if that community list was sorted. I believe it's sorting each individual page as that page is fetched, but not sorting the full list of communities.
I'll look into it because the GET /community/list endpoint (ref. here) accept Lemmy's sort types (Active, New, Controversial...) sorting and not alphabetical order. The other option, as it was before, would be getting the subscription from the GET /site but that does allow filtering and seems not to work if an user is subscribed to hundreds of communities (it happened in the past for someone complaining).