I'd recoil in horror at the traditional Disney take on a Tolkien story, though an impish part of me would quite like to see what Pixar could do with one of Tolkien's stories...
I think one of the big issues isn't particularly the 'look' of Disney animation, it's about how sanitised it is. The correct word is probably Bowdlerised. But, for the child viewer, much rewriting of stories is often necessary. The original AA Milne text of Winnie the Pooh is quite odd as I found when reading it aloud last year, but the Disney animations are acceptable. Another good example, though not a Disney interpretation is of Thomas the Tank Engine. The original books have some unpleasant stuff in them such as an engine being to all intents and purposes buried alive as punishment for being naughty. And there are numerous stories with serious or casual racism, cruelty, and dodgy values - even Narnia includes some attitudes I would not be happy for a child to take on board. What we deem as children's stories are not always suitable for kids.
The Hobbit itself has an authorial tone that's now quite jarring, though the content is mostly safe enough for school age children. However I feel Disney really would go to town on bowdlerising it. No trolls discussing boiling the Dwarves, or scary Gollum, and no really nasty spiders. Rather than Jackson's take which was to pick up and build on the action in the text, Disney would be more likely to pick up on 'silly' Elves and Dwarves - would the tra-la-la-lally be in there?
Oh yes. With Katy Perry singing
Disney's not all bad at all, I can see that some stories
do need to be altered for tiny ones to enjoy them. But some stories lose all their appeal when bowdlerised and The Hobbit would be one of them.
Of course, this is all assuming that a Disney adaptation would be animation, when we know they can also produce a cracking live action film (Pirates, anyone?). I wonder if Tolkien ever considered what a live action film might be like.