I only wish I'd read it back in college or even in high school, because this book says everything I've ever tried to say in class. (And gotten short shrift for saying.)
Characters only exist so plot can happen! Action reveals character, not pretty speeches! (Pretty speeches reveal thought and mindset, which ain't the same thing.) The dramatic unities are an analysis of contemporary best practice, not prescriptive rules!
Annnnnnd the "tragic flaw" is a good person's lapse in judgment. Mwahaha! I knew there was something wrong with that classroom definition of tragic flaws!
I see no reason why every creative writing and English major, much less the drama folks, should not read Aristotle's Poetics. If nothing else, it's full of good advice and good ideas. It's actually much less prescriptive than the average creative writing teacher. That makes it a good starting point.
So read the primary sources! Read them and make others weep!
"….one may string together a series of characteristic speeches of the utmost finish as regards Diction and Thought, and yet fail to produce the true tragic effect; but one will have much better success with a tragedy which, however inferior in these respects, has a Plot… beginners succeed earlier with the Diction and Characters than with the construction of a story… We maintain, therefore, that the first essential, the life and soul, so to speak… is the Plot; and that the Characters come second."
Sorry. I just had to savor that again. Characters come second. Style and characters are the easy part. Yes, Aristotle's got my back!