Wow! Just saw this thread for the first time. I'm not prepared to talk about any of the issues already raised yet, but I wanted to offer myself as an additional source, maybe to supplement the sources I see above.
I've been in editorial in textbook publishing for 20+ years. Some smaller specialty houses, as well as "biggies" with the multi-million dollar series (Houghton, Silver Burdett, Macmillan....). Recently I've worked in high-stakes assessment. But I didn't handle Georgia!
Anyway, I'll read at the links you've provided and see if I have anything to add. I just wanted to offer my perspective if it's relevant to discussion.
In textbook publishing, we often say: Textbooks are like hotdogs. If you knew what went into them, you wouldn't want to eat one.
(ha ha, "wouldn't want to eat one," we're a riot, we textbook editors)