Should new web features be HTTPS only?

I doubt anyone who reads this will disagree with the proposition that the Web needs to move toward all traffic being encrypted always. Yet there is constant back pressure in the standards groups, people trying to propose network-level innovations that provide only some of the fundamental three guarantees of a secure channel—maybe you can have integrity but not confidentiality or authenticity, for instance. I can personally see a case for an authentic channel that provides integrity and authenticity but not confidentiality, but I don’t think it’s useful enough to back off on the principle that everything should be encrypted always.

So here’s a way browser vendors could signal that we will not stand for erosion of secure channels: starting with a particular, documented and well-announced, version, all new content features are only usable for fully HTTPS pages. Everything that worked prior to that point continues to work, of course. I am informed that there is at least some support for this within the Chrome team. It might be hard to sell Microsoft on it. What does the fox think?