First, the accessibility argument is a red herring that I'm getting frustrated people continue to try to throw around. Screen readers support JS, okay? Let's put this argument to bed.

http://words.steveklabnik.com/emberjs-and-accessibility

Okay, thank you for letting me get that off my chest.

Second, one nice thing about "embracing 100% JavaScript" that I talk about in the post is that it requires you to implement a really solid JSON API, because your web site is now a true client that consumes an API. This makes it really easy to integrate with third-party services that consume your content. I agree that putting content behind JavaScript sucks; I'm just advocating that the content be JSON (or some other normalized format), not HTML.