A quick overview of the Classic Disney output.
The early days of Disney are really interesting. Lots of crude but cartoony fun, with the animation slowing building up over time with the Mickey Mouse and Silly Symphonies shorts. Disney's best period was easily from the mid-30's to 1942, when they were a animation powerhouse in every sense of the word-creating lavishly animated comedy or sentimental piece shorts (which are understandably hit or miss, especially today with people who are spoiled on Looney Tunes and Family Guy) which pushed the artistic boundaries of animation to their limits. Goofy, Pluto and Donald would also get short subjects of their own, with surprisingly fun results. The Silly Symphonies are lush, naturalistic fairy tale themed shorts themed around classical music—sickeningly sweet and tacky to some, but very pleasant for others. There are even some cartoony entries in that series like "The Skeleton Dance", the wonderfully cartoony and fun "Toby Tortoise Returns" and "Mother Goose Goes Hollywood."
From the mid-40's and onward, the Disney shorts gradually became more and more fomuliac, less cartoony and just uninspired compare to the standards they set during their Golden Age—it didn't help that the fast paced, cartoony competition had caught up to them by that point (i.e. Looney Tunes, Woody Woodpecker) and the fact that Disney was struggling through the 40's didn't help at all. By the 50's, Mickey finally gave up the ghost after limping by for the past decade, while Donald and Goofy would hold out till the 60's. In the meantime, Disney began experimenting with stylized animation and began moving away from naturalism and fantasy for more standard, contemporary settings and plots in their shorts, until they all but completely stopped production of shorts by the 60's and onward.
Needless to say, Disney's gold standard was set in their early years, when they truly were innovators and a animation giant in every possible way. The old 20's, 30's and early 40's Disney shorts are timeless, unique classics that have earned their place in animation history, and i hope will be cherished by animation nuts around the world forever. And with the upcoming Epic Mickey, it looks like the classics will be reintroduced yet again to a whole new generation of people who will enjoy and cherish them, just like the audiences of yesteryear who did the same.