Including their face.

I don't think this is necessary. What does seeing an officer's face do that a name and badge number doesn't? What about undercover cops? What about the winter when it's cold?

I think it should only be required that they declare on what authority they're acting when making official actions, like a stop, detainment, or arrest. They should give their name and badge number upon request, in a form that works for the asker (written or verbal, asker's preference).

If we ban law enforcement from wearing masks, that opens the door to banning masks in public. I get that police should follow higher standards (I'm absolutely in favor of ending qualified immunity), but IMO the rules should merely be that police must self identify in a way the public knows they're legitimate law enforcement when using the authority of their position.