[Matrixbeast]

Well, Mayu's return can be tied into revelations of the White Wizard (Since she's actually spent time with him, not just given a belt and some random girl to take care of), the only "Main" villains left are Medusa and Sora (Since, unless Wizard pulls an absolutely retarded move and introduces another villain higher up than Wiseman, we can assume he'll get axed in the last episode), so killing them off shouldn't be difficult or time consuming (Unless they want to pull more twists this late into the game).

But I agree that the slapstick will have to take a much reduced role and the time focused on asshole gates will have to take a backseat if they're gonna want to explain the likes of the Sabbat, Koyumi, and the Philosopher's Stone in a fulfilling manner.