Yeah I'd definitely say we should continue to follow our established best practices until G gets better at this but Josh's evidence and our continued testing on this subject is very compelling.
I'd argue that best practice in web development is not requiring JavaScript to load a page, but I'm sure that issue has been done to death in the past.
I agree on this one... just because Google CAN do it doesn't mean they will.
On that note, I am personally of the belief that the fragments are part of Google's learning/training process for their spiders.
If they sniff the XHR traffic on every domain they encounter a HashBang they can learn lots about the use of AJAX and the types of content being exposed via AJAX.