Meh, I still love Frozen, and I still think it's a really good movie. It wasn't the first time that the Walt Disney Company took liberties with the stories they were adapting. Hell, one of the greatest Disney movies ever, Mary Poppins, made the original author sob in the movie theater because she hated it so much ... But people unanimously love that movie (for good reason, too-- it IS a great movie).
If I had been in charge of making the movie, and the songwriters gave me a song like "Let it Go," then I 100% would have done the same thing and changed Elsa into a protagonist. You simply CAN'T unhear a song like "Let it Go," and shelf it. The whole sequence itself is iconic, whether people are sick of it or not.
The twist with Hans works for me in the movie as well, simply because the movie wasn't about "good guys vs. bad guys." It was about the two sisters healing their relationship, and I thought the climax of the movie was perfect for those themes. Granted, Disney has gotten OBNOXIOUS about "twist villains" since, but for Frozen, I thought it worked.