What makes Frozen feel shoe horned in to me isn't even the iP. Or the idea of a magical fairytale cartoon in the world showcase. I understand why these are deal breakers for a lot of people.
What makes Frozen feel shoehorned is that it doesn't fit or even attempt to fit the Norway Pavilion.
The Norway Pavilion, like most World Showcase Pavilions, was built to be in modern day. Set up as a mix of different architecture styles blended together to for a more or less modern snapshot of Norway as a whole.
Then you enter some modern looking building and immeadietly and harringly find yourself in Arrendelle.
There is no, none, zero effort to blend it into the current pavilion.
If they redid the pavilion as a whole to reflect medieval Norse architecture of the kind that inspired Frozen (similar to the idea behind the absolutely wonderfully done Royal Summerhaus area). Then the transition to Arrendelle wouldn't be so sudden and jarring. Or perhaps redo the line for the ride to start off as a museum about the influences of real Norse culture, architecture, fashion, and mythology that influenced Frozen transitioning into the ride (a more on the nose version of how Maelstrom transitioned you into the ride). OR redo the entrance/exit/shops so the entrance to the queue is next to the Summerhaus instead if the main section of the pavilion so it doesn't clash as much.
But how they did it was lazy and shoehorned in