I think we'd be a bit more direct than Mr. Israel and just say yes, we think metadata should be a category of protected data. I think there's been sufficient jurisprudence now to suggest that metadata can be very revealing of intimate personal details about the biographical core.
On the actual mechanism for doing that, perhaps regulation is great for the detail, but in terms of a general purpose statement as part of the kinds of information covered, we'd love to see that placed directly.