Honestly, as excited as I was for the new show, the final product is a bit of a mixed bag for me. BUT, it's not "ZOMG THEY'RE RUINING MY CHILDHOOD"-worthy. It's just... there.
The show borrows heavily from Tokyo's iteration but I feel it works, it's not simply the Tokyo show ported over to Disneyland. The lead female vocalist is trying a bit too hard and is overused in the show (in my opinion), and the finale vocals are a bit too "modern" for my taste. I feel like the Pirates section is unnecessary, it's the 2006 additions to the attraction if you replaced "WHERE BE JACK SPARROW" with "WHERE BE MY COMPASS". I like that they reused as many of the character vocals as possible, and Bret Iwan does a pretty awesome job as Mickey after only nearly 10 years voicing the character. I do feel like the Finding Nemo and Little Mermaid section was kind of pointless in the show, but that's a minor nitpick.
Overall, I don't love the show as much as I love the original, but it's not completely horribly terrible either. Steve Davison and crew played a pretty good hand with the cards they were dealt, but of course anything can be improved.