I read a couple of online reviews that said they think the reason Frozen is getting so much attention is they broke the Disney "MO". Everyone assumes that she's going to fall for the prince and live happily ever after and many assume the ice sales guy is going to wind up with her sister.
So the "shocking turn" later in the movie throws everyone for a loop. The adults that assumed they had the whole formula figured out go hey, they actually changed the plot on this one. And the kids go whoa, that prince was a bad guy?
JL changed the Disney model that's why. They adopted the "PIXAR WAY" of developing story. It's only natural the way Disney struggled aside from PIXAR films that they would follow his lead now that he is the man in charge.
For example they now let new directors cut their teeth on short subject animation before granting them a feature length film to helm. They also implemented the philosophy of making it a filmmaker-driven studio, not an executive-driven studio. They also implemented the Pixar "BrainTrust" method at the direction with a version called "StoryTrust"
So, even though Disney broke the MO, I doubt they get completely away from it but they will approach story differently going forward. It's a good thing. It has really shown in the last 3 of the 4 films (Planes was horrible).