"Those authors who have not paid attention to this part of their craft (rhythm) have produced writings which are either mean or diffuse, or have some other deformity or disfigurement. The first, middlemost and last in this is that sophist from Magnesia, Hegesias. Concerning him, by Zeus and all the other gods, I do not know what I should say. Was he so insensitive and dense that he could not envisage which the ignoble or the noble rhythms are? Or was he so bedevilled and mentally deranged that he still chose the worse, though he knew the better? I am inclined to believe the latter: for it is a characteristic of ignorance that it often lands on its feet, wilfulness never does. At any rate, in the large volume of writing which the man has left behind him, you could not find a single page that has been felicitously composed. Indeed, he seems to have supposed that his way of writing is superior to that of his predecessors, and to have practised it with enthusiasm; yet any man of sense who fell into such errors under the stress of impromptu speech would feel ashamed." (De Compositione Verborum, 18)Dionysius goes on to quote an excerpt from Hegesias on Alexander the Great and then compare it unfavorably with a similar episode from Homer's Iliad. He closes with this last jab at Hegesias:
". . . the manner of description used by the Magnesian could be adopted only by women or emasculated men, and not seriously even by them, but in a spirit of mockery or ridicule. What then is the cause of the nobility of these lines (from Homer), and of the miserable inadequacy of the other drivel? The main cause, if not the only one, is the difference in the rhythms. In the passage of Homer there is not a single undignified or undistinguished line, whereas in that from Hegesias not a single sentence will fail to give offence."W. Rhys Roberts identifies the use of double trochees as the primary offense that made Dionysius' poetic blood boil. Let that be a lesson to you: watch your trochees. Hegesias of Magnesia is typically considered the founder of the Asianic style.
(De Compositione Verborum, 18)
Dionysius was not alone in his criticisms of poor Hegesias. Cicero also had a few unkind words of his own:
"Hegesias . . . was so vain of his own taste for Atticism, that he considered his predecessors, who were really masters of it, as mere rustics in comparison of himself. But what can be more insipid, more frivolous, or more puerile, than that very concinnity of expression which he actually acquired?" (Brutus 83)If something you write ever gets an unfavourable review or grade, just remind yourself of these passages. As long as your work is not being called "drivel" or "miserably inadequate" then you're still ahead of old Hegesias.
You can read up a bit on Hegesias here and here.