>"tenant admins will decide whether to enable it and require end-users to opt-in. Ouch"

This is a deliberately alarmist interpretation of the feature being opt-in. I don't think there's anything to see here.

It's on the wrong end of the phone for pocket-based use.

No it doesn't, at least on my device.

The Mine project (http://themineproject.org/) exists to allow exactly this.