Disney's all sugar concept was good for the time it was invented, and for almost 3 decades years it worked ok. It was very simple, but incredibly succesful at the same time: use an old tale, change so it's not too scary (Grimm's specially) and add a few nice songs. When Disney died it took the studio 20 years to get back to making classics (they abandonded the old formula, and the original stories formula didn't work).
They rethought the idea in the late 80's, and what they come up with was good enough for me, and I consider them to be classics , maybe in a different way that the old ones. I'm taking about Little Mermaid, B&tB, Aladdin, Lion King,... They realised they had to update a concept a bit, so in most cases they had some, let's say, less childish humour. In Aladdin it's crystal clear: Abu for kids and the Genie for adults. And it worked ok for some years. Why? Because it was good and there was nothing else.
And then Dreamworks and Pixar came into scene, with a different aproach: what if we write scripts in which kids are not the main targets? And voilą, it was a revolution in animation: it was not only for kids anymore. Something the Japanese have known since they started making manga and anime, and that was not that clear in the western world. When I was a preteen, going to see a Disney movie was like embarrasing (cause they were for kids). And now, both pre-teens, teens and adults are eager to see the new Shrek, or the last Pixar. Cause they are adult movies. And what's great for the studio is that the old idea of animation is for kids is still floating around, so kids are still eager to go to see Pixar movies. Let's make money.
Yup, I agree with those last opinions. The fact that Ottman reused Williams themes just means he's not insane. Superman is too much an icon to change it. Doyle, as Peio appointed, is a serious composer. He just tried to make his own Potter.