"The Doctor" is an ambitious episode that, by bringing in the Dr. Frankenstein character, exponentially increases the scope of fictional sandbox in which our writers play. Oh wait, before I get to that, I mean to comment on the Whale/Frankenstein connection. That slim clue I mentioned -- the one that the supposedly unspoiled speculator used as the foundation for speculating that Dr. Whale might be Dr. Frankenstein, is this: the director of the original Frankenstein film adaptation is none other than James Whale. As soon as I read it, I knew the speculation was right, but it wasn't too long before I also felt like I'd been tricked into spoiling. So, there you go.
Now about our newly enlarged sandbox. I talked with friends about this early in the week. My friends Robyn and Ginger can accept (to some extent, grudgingly) that the different fairy tale characters live in adjacent worlds, and that Oz and Neverland, while not traditional folk stories, are sort of cut from the same cloth. Still, they're not crazy about the idea of making the sandbox so large that it even includes Frankenstein. They find it jarring.
On the other hand, I'm thrilled by it, as is my friend Jenn. Since Victor needed the Mad Hatter to get him to the Enchanted Forest Universe, I didn't find it jarring, at least not in a bad way. When we had Jefferson's episode last season, and he took Regina to that room between the worlds (and then to Wonderland), I took that as a promise that we'd be getting more than fairy tales. If Victor could have gotten back to his world on horseback, then I would be upset.