I really want this to be possible again as well (I also hate the new look of the faded stars for anything that isn't rated, although I suppose I'll get used to it).
That said, one sort-of work around that is working in the meantime is to use another app to read/write the star ratings. I've been using an app called Song Rating for a long time that sits in the menu bar and displays the rating of the currently playing song. It has an option to enable half-star ratings, and it will read the proper half-star ratings from the songs when they start playing, while also allowing you to write half-star ratings to the songs by rating it through the app.
Sucks that you still can't see all of the proper song ratings in the list in Apple Music, but at least I know they're still there and am still able to rate that way if they ever come back in a future update.