"The great virtue of Disney films like Lady and the Tramp was that they showed that such animation is possible. Their great vice was that they seemed to say, in a louder voice over time, that such animation is possible only in children's films.
As a result, the temptation, if you're making more "adult" films, is surely to shrug off the Disney animators' lessons; but there's no way, if you're doing that, to achieve the emotional strength of their best work. A lot of animated filmmakers seem to think that they can work around that problem by making "story" their mantra, or by simply ignoring the question of how to give animated characters a vivid presence on the screen. But such dodges never succeed. It's only by meeting head-on the challenge of making the characters in their films as real as the best live actors that animated filmmakers will ever escape from the ghetto to which they have been, so far, rightly assigned."
Tough words...but I know what he's talking about, and I suspect most of my colleagues do, too.
To turn Barrier's premise inside-out, though, there have been some Disney films where "story" took a backseat to characters. In that category I'd put "Sword in the Stone" and "Jungle Book", both films I saw and loved as a kid and still love--but mainly for the performances of such as Shere Khan, Archimedes, Merlin and King Louis--not for the relatively weak story/plot and the corniest gags that are in them. Were the characters in those films not as entertaining and real as they are, there'd be pretty much nothing there but color and movement.
It's been said by wiser heads than mine that in the latter days of the nine old men, they were actors without a worthy stage, much like Laurence Olivier giving it his all in "Boys From Brazil" or "The Betsy". Feature animation was in a general doldrums; the kidvid ghetto was going full bore on TV, and there was no guiding hand at the world's most sophisticated animation company. It seemed to operate on the inertia of a more energetic time.
I think there are definitely pitfalls in having a story "mantra" that ignores just who's doing what in a film, though it's never intentional to sacrifice personality for plot--the aim is almost always the opposite, in fact.
Maybe there's a perception among non-artists of animation as having some sort of special needs, since our characters aren't seen in early development as castable flesh and blood actors, but are drawings and designs.
Of course the very, very early, embryonic beginnings of a feature film are a story's premise. If there isn't any story there to tell, well, that's trouble. It needn't be at as big as an epic, it can be small and even personal--but in the end it has to connect with a wide audience, and more than plot it's characters who carry that burden.
So to continue and develop that premise, assuming the story has something to work with it really does depend on the characters(that goes for the great shorts as well: Bugs Bunny trapped on a desert island is a hell of lot more interesting than Barney Bear trapped on a desert island or a Genericized Rabbit in that situation).
The story of a father fish looking for his lost son...okay. The story of a terribly neurotic, xenophobic, keep-to-the-reef father fish forced to plunge into deep seas, teamed up with various creatures he'd never want to deal with, but does it anyway, struggling all the while? Much better.
One doesn't want the plot running the characters, one wants the characters to be the plot--to make it their own one of a kind story, if you will. But(remembering "Sword in the Stone")they still need something worthwhile to do, and in a long-form story it probably can't be a one-set premise(never say never, but to generalize). No "Waiting For Godot"s. Pinocchio should get out of Gepetto's workshop. But personally I don't see any way forward in any story without nailing down the characters first. I have to know this person if I'm going to make drawings of them, and especially if I have to have them do or say anything.
Ideas come from drawing; good drawings--great drawings--come out of acting, the old "acting with a pencil" canard. It's really true. The more you know and love the characters, the more options for entertainment you'll have. They'll take over a scene in the same way novelists describe, with their characters. If you're taken in an entirely new direction, and it's going to work, it might be a very good thing when strong characters hijack you.