I appreciate the argument in favor of filler episodes, that some breathing room is good and that not every episode needs to move the plot forward, but in my opinion it doesn’t go far enough. Bring back purely episodic shows. Jessica Fletcher doesn’t need forward momentum; she’s too busy solving mysteries.
Emphatically yes. I realized at one point that that's one of the things I loved about mysteries: a certain set of fixed axioms (such as Jessica Fletcher writes novels) and then an endless fount of stories built on them. Same with “Columbo” and “Ellery Queen” and “Miss Fisher's Murder Mysteries” and on and on.
But it's not specifically a mystery thing (e.g., “Stargate: SG-1”), any more than mysteries are necessarily purely episodic (e.g., “The Apothecary Diaries”). Mysteries are making a comeback; let's have episodic stories make a comeback, too.