I can't really say if Google is taking this approach to secure a device from heavy handed enterprise admins; but if true, it's gone too far by allowing only the app from having private conversations with the api and not allowing the user to see what's being sent over the wire.

This isn't exactly new, we do after all, have certificate pinning. But now, this certificate pinning is done at the OS level by DEFAULT, un-trusting all certs except the ones that Google deems fit.

We know that there have been un-trustworthy Certificate Authorities that all our machines have trusted until its been deemed unworthy by our vendors... and eventually expunged! But this change explicitly un-trusts us, the users of our own phones -- in the name of security.

User deftnerd (https://news.ycombinator.com/item?id=12061342) had an excellent suggestion that the trusting of user added certs can be relegated to the TPM module (via password, passcode, fingerprint, etc..) -- not by the heavy handed approach of simply blocking us out of our own phones conversation.