In "An Ordinary Man", it was time for Louis to do his "going secretly amongst the people" routine, a rite of passage all kings of note must endure. But of course everything went wrong, because otherwise there wouldn't be an episode. Kidnapped with d'Artagnan to be sold into slavery, it was time for Louis to actually listen to the common folk and see how little his rank means in the real world. Would that lead to a change in worldview, causing Louis to become a wiser and gentler king? Not so much.
With Rochefort, that sneaky bastard, we got a glimpse of his limits. He might be willing to bring down France, but that doesn’t mean he wants to actually kill the king. Constance, as Anne’s new confidant, is the only real obstacle to him in that regard, and that brings up whole new issues. Because Rochefort can fight the musketeers physically, but he has to fight Constance diplomatically. And if there’s anyone who can stand up to him, it’s probably Madame Bonacieux.