Thad writes that Kimball was Disney's "most original animator" and I think that's definitely true, though I don't think it's always a compliment. Kimball had a unique style; he did the cartooniest animation of any of Disney's "Nine Old Men". And whereas the other animators toned down as they went on, Kimball actually got broader, so by the '50s his scenes and characters (like Lucifer in Cinderella) are all goofy moves and rounded shapes.
The result is that some of Kimball's scenes seem to belong in a different movie -- though I hasten to add I'm not talking about the crow scene in Dumbo. But the stuff he handled in Cinderella, all the stuff with the cat and the mice, really doesn't seem like a full-fledged part of the movie. Though, of course, it probably would seem that way no matter who animated it: the cat/mice stuff is the weakest part of the film, not because of Kimball but because it's what you see when you look up the word "padding" in the dictionary.
Amid Amidi's piece on Kimball makes it clear that his work didn't completely fit in with the way Disney's features were developing, and other films utilized his talents better:
While Kimball brought to life many of the now-classic characters and moments from the Disney features, it became increasingly apparent by the late-Forties that Kimball's talents were not being utilized to their fullest extent as an animator. It wasn't until the Fifties, when he made the switch over to directing and producing films, that his sophisticated graphic sensibility and humorous and intellectual tendencies found a receptive home.
I should add here that I have a lot of admiration for the less cartoony animation in Disney's early-'50s features -- a lot of people seem to think it was just a matter of duplicating the live-action reference, but I think there's more to it than that, and there are many touching and beautiful moments in the animation of the human, drawn-from-life characters. I think some of these characters, because they are based on live-action acting, are a bit underrated today.
Addendum: I just found Kimball's "What Makes the Red Man Red" sequence from Peter Pan -- dubbed in Arabic.
I find it odd, by the way, that the Disney company doesn't feel obliged to include some kind of disclaimer before Peter Pan on account of this sequence. Not that I want a disclaimer, mind you (and I was horrified when I heard someone argue that Disney should have cut this scene out to make the movie less "offensive"), but it's weird that the company includes all kinds of disclaimers for any other racial stereotypes, and still doesn't have the guts to release Song of the South, and yet this particular set of stereotypes doesn't seem to worry them at all.
Oh, and one other thing: is this the first time someone had used the gimmick (later to become an animation cliché) of the tracking shot into a character's mouth?
Update: It wasn't the first time, as Thad explains in comments. But Kimball sure seemed to like that particular gag.