I get that. Some people like that premise. I find it groan worthy. Sat through it once, never again.My issue isn't that the show does a book report storytelling. That's exactly what people expect, and especially in a branded theme park environment there's nothing wrong with that (so long as that's not the only kind of entertainment available). My main issue isn't even the script or the actual production of the show (though neither are great). It is primarily adding songs to a story that was originally designed without them, particularly when the original source material in question is a ~90 minutes animated film.
It almost never works, and the only time it does is when the creative team looks at the source material from another angle, and/or is trying to say something new or deeper about the original work or characters.
Too often, though, it turns into "take this moment from a property you love, but now it's a song." Almost never a good one either (if "Big Blue World wasn't in the Nemo ride at Epcot, would anyone know it? Are people going to remember the other songs at all? Not likely). That, regretably, is Nemo in a nutshell.
Now, Disney is not the only company that has ever done this, but it is a personal pet peeve. It's precisely what people who hate musicals imagine them to be like. I would rate the show much higher if the songs (that add nothing except length) were removed, but even then it would hardly be as exceptional as people proclaim it to be. .