Disney, I have noticed, has had an immediate decline in animation and story quality over the past few years and that really shows in this movie.
Comparing this to the art book, it is very obvious that cooperate medaling form Disney heads RUINED the art behind this film. The concept art is very lively and has the soul of old Disney films unlike this grey, bland and sad result this film ending up going with. Changing the lead music director was another horrible change, the songs don't feel like they are a part of the movie, they don't suit the environment it is set in either and the visuals paired with the music doesn't help. Other studios like DreamWorks and Sony animation are leading the fight in animated movies, Disney needs to take some notes.