Hi,
I've not seen any comment from Googlers regarding this debate. I realize I'm keeping this in the Moz-sphere, which isn't quite what you're looking for, but this quote is from Moz's domain setup guide:
"Since search engines keep different metrics for domains than they do subdomains, it is recommended that webmasters place link-worthy content like blogs in subfolders rather than subdomains. (i.e. www.example.com/blog/ rather than blog.example.com) The notable exceptions to this are language-specific websites. (i.e., en.example.com for the English version of the website)."
I think that quote is pretty compelling towards the subdirectory side of this quandry. I also recommend checking out the comments on the Whiteboard Friday link you posted, there is plenty of evidence there as well.
Unfortunately, this debate will probably go on forever until we get definitive word from Google.