An (intuitively) working search would be a great step ahead. It should find and show things if they exist, and only show no results if they do not. That a plethora of external tools exist to meet these basic needs shows both how much this is needed, and how much it is broken.
I also feel I have more luck finding communities if searching for ‘all’, instead of ‘communities’. Don’t make me add cryptic chars to my search to make it work. Do that for me in the background if necessary.
It’s been long since I’ve been using it, but iirc, it’s impossible or painful to search for a specific community in your subscribed list.