At some point, book buyers (like me) will stop buying digital books from Amazon if we can only read our books on Amazon's ereaders
This would be a concern if not for the fact most people don't seem to care. Kindle ebook sales are trending up, not down. Also, in making this point he ignores the fact that you can also read Kindle ebooks on Android, iOS, OSX, and Windows.
The Kindle is less valuable, less useful, if I can only read Amazon purchased books. I want to be able to purchase books from Google and from Barnes & Noble.
I could just let this one speak for itself, but I'd rather skewer him. Is there an ebookstore with titles you can't find in the Kindle Store? Google, perhaps, but I seriously doubt that anyone else can make the claim. Also, since you can have multiple apps on your gadget (PC, iOS, Android), does it really matter which app opens the ebook? Amazon can afford to lose the handful of sales due to ebooks they don't carry. Their prices will bring you back on the next one.
Enable and Encourage Sharing
This isn't something Amazon can change, so there's no point in proposing it. Ebook lending is being blocked by the copyright holders, not Amazon.
Partner with Digital Coursepack Providers
This is an excellent idea. Amazon really aren't putting any effort into getting digital coursepacks into the Kindle store. It's an untapped market segment which is could be larger (in $) than the textbook market. (Actually, I'm not sure they're in anyebookstore. Mist look into this.)
Bundle E-Books with Audiobooks
I don't think the market's there. Everyone's been talking about ebook bundling for the longest time now, and yet few are doing it. Also, what is the value in bundling an audiobook when the Kindle has TTS? It's not as good, no, but it doesn't cost anything extra.
Build Library Partnerships
This is another good idea, but it needs to be expanded to schools and other institutional buyers. They're valuable not just because of how much they spend, but also because each library with a loaner Kindle is a floor model Amazon didn't have to pay for with a sales staff Amazon didn't have to hire. There's no downside for Amazon.
image via Andyl