Evening. I don't normally read your blog.
1) "If Apple doesn't approve your book, you can't sell it anywhere else." I don't think that's entirely true, really. If Apple won't sell your book, you still have ownership of all your content, and you still have a choice: you can recreate it in any of the other non-existant EPUB3 creators, you can export to PDF (or Text) to shop it around to a design or preproduction company who can reformat it for a cost, or shop it around to another publisher who would then, also, reformat it per their needs (at cost). Apple's disapproval of your content doesn't dash your hopes of being published - it just dashes your hope of using Apple's technology to distribute your book.
2) "If you create an ebook in iBooks Author, can you then copy out the content and create a Kindle book in some other tool?" I would say "Yes". Apple is not copyrighting your content, it's taking control over the presentation of your content, as created by iBooks Author. I don't think that's any better, mind.
4) "iBA ebooks will work only on iBooks on iPad" I don't really see this as an important distinction: heavily-laid out PDFs are difficult to read on the iPhone's small screen too, enough so that it's usually not even worth the bother. Apple didn't bother either.
5) "It certainly can't export to any other format." iBA can export to PDF and TXT, and as another commenter mentioned, the source/bundle contains an XML file that can be parsed and converted to other formats as well, given enough effort by an enterprising hacker.
6) "Apple's iBookstore currently serves only 32 countries." As someone who only speaks English, "I don't much care". I know, I know, what a horrifically biased and locality-centric discriminism. But, it's nothing new. DVDs, Blu-ray, video games, hell, even goddamn power plugs, are locality-centric too, and you have to pay an arm-and-a-leg to get around it. Most people don't. I suspect that most of the normal end-users of iBA won't really see a loss in not serving to English-speaking users in Russia, or recoup their cost of translation to serve native-speakers in South Africa.
7) "Apple iBookstore is not that great." Heh, no complaint here. Note, however, that the only ebook store I've used that was actually useful has been Amazon's, which only works because, erm, well, it's not an ebook store. Google's eBooks isn't much better than iBooks either. Your lament here can apply to pretty much any current eBook store.
10) "This is about books (for teaching our children!) which in my opinion should not be controlled by any company or government." "for teaching our children!" is a disingenuous and heart-stringing tactic - there's nothing in iBA that forces you to write textbooks for children. Or high-schoolers. Or college people. Why aren't you as angry at Inkling for being iPad only? For being a closed-source format? For offering textbooks on, gasp, how to mix drinks?! FOR OUR KIDS! I suspect a good portion of the individually-created iBA books (vs. corporate books, like DK, Pearson, etc.) will be non-textbook-y and crappy (and those that ARE written by individuals and ARE "textbooks for children" will likely unleash a backlash of "how dare Apple let just anyone create books to teach our children!? OUR CHILDREN!").
I think the "right" approach, for me at least, is to change the Eponymous You's goal statement from "I want to write a book" to "I want to write a book FOR THE iBookstore". The added clarifying statement, RIGHT NOW, opens up an entirely different world... one that includes a WYSIWIG book creator and added interactivity that is difficult to implement or non-existent in other readers. With that goal statement in place (as opposed to the far-easier "I want to write a book"), the "only" downside is that Apple can deny your book. Otherwise, the other laments nearly disappear or become acceptable.