Requests for live DM mode and a public or private 4 w/1 session, assuming a capable player/game tagging system -from Role Play to Just Come At Me Bro:
1. Live GM able to possess and place any creature or object including a player character. w/accompanying permission toggles. Friends can set GM permissions to full, strangers can look for games with GM permission toggles set to what they are comfortable with. Full control to very little control.
In my opinion, if maximum live GM control is the goal, everything else will fall into place and provide for a pleasant gaming experience.
I'm a frequenter of the Sword Coast Legends forums. SCL's approach of "ease of use" regarding a GM (DM) throwing together a quick module and stocking on the fly is pretty cool, unfortunately they have sacrificed DM/GM control for balance by going after the pick-up-game-with-strangers crowd -a type of game play that screams "Balance this!"
This seems to have created more balance questions than it answers and pretty much indicates to me that giving folks the options of joining games they like or agree with the permission settings, is the very best way to proceed with a live GM mode.