The only real knock against “Mortshall” is that “Rick and Morty get sick of each other and split up for a while” feels kind of old hat at this point—the comic premise of the show requires their relationship to be toxic (because a lot of the humor comes from seeing Rick be a shit and seeing Morty try haplessly to deal with Rick being a shit), and they can only try and sell the illusion that anything is going to change so many times before it starts to get stale.