They even salvaged something that I would have sworn wouldn't have worked--Dory's dreadful "Just Keep Swimming" ditty is turned into an actual musical number. The humor of that ditty in the film is that it's a stupid, tuneless piece of crap, so I would have said you'd screw up that humor by making it into a real song. But it works, and not only does it work, it's reprised by Marlin as he hovers over the consciousness-losing Dory after she's been stung by the jellyfish. It was pure Marius and Eponine, I'm not making that up.
Only beef? They castrated Gill, man. Or whatever it is you do to male fish. Gill has one song and it's all "we can do it if we act together," which, blah, is nothing like Gill. Gill's a cynical loner ready to risk others for his own agenda--or sacrifice himself for theirs. I had to go read my own fishslash fic to take that taste away. Gill/Nemo OTP, man.
(And, yes, a week at WDW always leaves me with the urge to write Disneyfic.)