@Keb wrote:
I think that she was called the original power, but not more powerful. I believe that dark magic is more powerful than anything but true love, because the price is high. Regina had to sacrifice what she loved most to enact the curse, and Rumple’s deals are mostly about making sure he’s not the one paying the full price for what he does (though he, too, lost a lot–including most of his soul and his son–for his power).
I don’t think that BF is capable of paying the price for dark magic, and so her power is far more limited. They’ve said that it requires a pure heart to get her to come, and she seems capable only of granting a very deep wish under particular conditions (like being selfless, brave, and true or whatever–it’s said that August couldn’t have been transformed if he was not).
Also, it’s been suggested that two magic users are stronger than one–Rumple needed Regina’s help to create the portal-block when Cora was coming. Rumple’s also, by far, the most experienced magic user shy of BF, so his shield was probably a lot stronger than Emma’s. Cora and Regina together broke that shield the first time; Cora struggled a lot harder alone with Emma’s second shield.
Keegan said in an interview that the script said The Blue Fairy is the most powerful being in all the land.