How does one write a less than stellar review of one of the greatest works by the greatest philosophers of all time? By describing its readability vs its value received.

First, if you have read any decent summaries or discussions of Aristotle's views of poetry and literature (even on grammar), there is very little different here, though perhaps due to translation a bit more confusing in places. If you have not, scholarly summaries of his views are more concise and revealing for the basics. The Poetics is brief, and Aristotle wastes little time is diagramming and categorizing his subjects: what makes poetry/drama worthwhile and how does one know? 

Reading the work directly also comes with some surprises. I did not realize, for instance, how much time Aristotle would spend (especially in the second half of the work) discussing the historical nuances of Greek grammar in terms of literary function. For this alone--as almost literally unapproachable for me--if you do not read Greek, this part of the work isn't very accessible!  Confining the rest of this review to the broader discussion of literature in the first half, then, I was gratified to see him cite so many examples of poetry and performance of his day, naming works and  writers as historical and contemporary, and weighing their artistic skill alongside one another.  Spoiler: Euripides is one of his favorites.)

All in all, however, I left the work having learned little that I had not previously studied. On the other hand, I had a better appreciation not only for what the philosopher established for Western art, but how narrow and limited that foundation has since become for the imaginative possibilities art now explores.