The realistic walk is just one way of walking in cartoons. Cartoon animation shouldn't resemble real life per se, you can do much more than that, it seems. If you study Disney animation on DVD (especially the walks by Goofy), you'll see something strange happening, broken joints, where the joints are bent in a unnatural position.
And even life actors can do so much more than mere walking. Have you ever seen the Monty Python sketch "Ministry of Silly Walks" ?
