That's essentially how it is now, +Brian Turner
. As a H/P I can Mute or Unmute any participant who is also using Pro Studio regardless of how they were previously muted/unmuted. Currently, the only enforced limitation in changing to either state is that the participant cannot Unmute themselves if they were Muted by a H/P.
The other side of this, for me, is that a participant may Mute themselves to keep a conversation private from the Hangout and a H/P may Unmute them during that conversation, which I consider to be a bad thing. I began walking down this road thinking that, if they muted themselves, then they'll know how to unmute as well, but Pro Studio is not the only other way that people can be muted.