If they ever go in the direction of shutting off microphones, it needs to be like a chess clock — each candidate gets 40 minutes. No more. No less. Moderator gets 10 minutes to ask questions. The clock is ticking while you speak. You stop your clock when you turn off your own mic. Or someone else shuts you off.
I think it is a fair observation that Democrats always get more time to speak than Republicans. If the moderator gets unilateral power to shut off mics, this disparity will become more extreme.
Actually in fairness, those who track these things noted that after Pence rolled past the clock, the moderator and heels-up the time count was pretty even. But Pence had to cheat like hell to get an even break.