Stop looking at voice chat as a bad thing
You're not obligated to use it or listen to the people who are going to use it to be toxic; muting people / turning your voice audio off is ok, people will still ping.
Going against a team with 5 players with mics doesn't make them TSM either, it's just a clearer and quicker way to call.
Even if you have a mic and you're on a team with 4 other guys who have a mic and are the nicest people in the world, you still have a good chance at losing the game.
I play DOTA (I know) and CSGO and some of my favorite pugs and great people I have met have came from fun enjoyable people that I talked to via voice chat. It's going to have bad people, but we're faced with bad people everyday already and we'll handle these people the same as we do already mute and move on. Please don't write off this great feature without it being out yet.