All art is defined, in part, by the constraints under which it is produced. String quartets don't normally call for a saxophone solo. Symphonies are generally multi-movement works with the first movement in sonata-allegro form and the final movement in either sonata-allegro form or rondo form.
In a Coyote/Roadrunner short,
1. Nobody speaks.
2. The Roadrunner makes no aggressive moves beyond beeping or sticking his tongue out, and never leaves the road for the purpose of avoiding the Coyote's schemes.
3. The Coyote's schemes are always overly complex, and always backfire.
4. The Roadrunner always escapes.
Pocket is not in the business of buying "Mary-Sue" books from new authors, and they only rarely buy them from established authors (and even then, they have to be far better than anything a new author is likely to produce). You want to write a Mary-Sue book and get it published? Do it in your own milieu.
Personally, I think it's a crying shame that the "Strange New Worlds" anthology series was discontinued.