Wish is a movie with catchy songs and an inspiring story. It's a story about ideals and a movement to claim back individual rights, which is a refreshing direction from the usual stories of a fairy tale princess and a villain. Watch the movie with an open mind and no expectations, and it's very enjoyable. Go in comparing any movie to the "old Disney you know and love", and you'll hate it no matter how good the movie is. I have my own gripes with things like the lyrics and wanting some characters to be more fleshed out, but the overall experience was VERY enjoyable.
A lot of people online were hating on this movie before it EVEN CAME OUT, and then still went to see it to hate on it more. People kept saying they wanted a good old "plain evil villain", then hate the villain for being "generically evil". Then they hated on it for having Easter eggs, despite it obviously being a 100th anniversary film. Criticisms are well and good, but much of the online tirades are very bandwagon-y with expectations that were a mess in the first place.