Even that crossover with The Critic makes more sense than this. (And we'll probably be forever denied a Futurama crossover outside the comics.) Mind you, crazy crossovers aren't a new concept, but usually those shows have the same creative team, or plausibly exist in the same universe. Green Acres, Petticoat Junction, and The Beverly Hillbillies crossed over all the time.

Even with the same creative team, The Charlie's Angels gang taking a cruise on The Love Boat still feels weird to me. Ditto The Green Hornet showing up on Batman.