Malachy is right, the HowlRound blog post by Mat Smart caused quite a kerfuffle in the theatre blogosphere and on Twitter. (And by the way, if you want to follow some really great theatre conversation, check out the 2AM Theatre blog and follow the #2amt hashtag on Twitter.)
I thought I'd add to your reading list and direct you to some of the online responses playwrights wrote to Mat Smart.
Playwright Kari Bentley-Quinn takes issue with several of Mat's arguments about "lazy" playwrights.
Playwright JC Lee wrote two responses to the HowlRound blog post.
And Youngblog, the official group blog of Youngblood had two posts by two of their playwrights contributing to the conversation.