Many critics like William Deans Howells; T.S. Eliot etc. have called Jonathan Swift the greatest writer of prose like T.S. Eliot says that
"Swift, the greatest writer of English prose, and the greatest man who has ever written great English prose."
But there are reasons for this greatness. One of the main reasons is that Swift wrote in a very plain and downright style. He didn't use any embellishments. At times, when Swift was writing serious stuff this same plain style appears dry but when writing humorously, this same plainness gives his wit a singular edge. Swift didn't use ornate or rhetorical language; he said what he had to in simply without any affectation as Hugh Blair says
"His style is of the plain and simple kind; free of all affectation, and all superfluity; perspicuous, manly and pure."
And at times, his style appears so simple that its seems like anybody with a little sense of writing could write like him but in this same simple ness of manner lies Swift's greatness like Scott says
"Swift's style seems so simple that one would think any child might write as he does, and yet if we try we find to our own despair that it is impossible."
This same simplicity of style in Gulliver's Travels corresponds to the naiveté and simplicity of Gulliver.
Another important feature of Swift's prose is that he uses the common touch. In other words, everybody can understand his language that is why even children can read his books with so much enjoyment. Also, Swift addresses people as rational and political beings, making them his equals. For example, in Drapier's Letters Swift uses the same language of the class which he is addressing i.e. rough and shrewd. Swift doesn't write long sentences or speeches or difficult words. And he familiarizes with the people by using their own simple and at times coarse language.
Invention or imagination is an aspect witch makes Swift one of the greatest...