The thing is, they've set up all those possibilities already. They did an AU episode. They did an episode about being unsure if you were awake or in the Metaverse. They've committed to this whole storyline about Diane using mind-altering drugs, which in fact was triggered off of the Metaverse episode. And all the while, reality has been getting weirder and weirder. If it turned out that this whole season diverged into All-A-Dream at that point, they've done all the groundwork they need to justify it.

I think it's much better storytelling if it's the opposite, if they've been using their flirtations with All-A-Dream as devices to set up just how weird reality has become, but... we'll see.