I mean, do you know the Overwatch voice chat system ? I think they got it handled pretty well. If u queue up in party u are basically in your party voice chat...u have to manually switch to the game voice chat to be able to communicate with others...And toxicity...there are lot of individuals that would act just totally different as u described...Many kids are just too shy to speak and reveal their shinny little voice. And if not..u can just simply mute or leave the voice chat, if same system would be implemented (the one i mentioned above). Lets look at actuall advantages here. You would argue that pings are enough, but i highly doubt, that below diamond or plat (in some case even master+)people even notice them when you are just focusing so hard on your csing while dodging all enemies skillshots or timing good flash when u are being gank...(u get my point right). Just imagine that jungler would just say jungler: "Hey dude looking for gank top...can we ?" laner: "Sure dude, just wait a sec till this minion wave focus the tower so i dont take so much dmg from them". This thing simply cant be pinged or typed in chat while playing...There are plenty and plenty of situations when u cant type or ping about that...When i soloq i just want be able to communicate with my teammates properly. When u look at those top competetive games like OW, CS, DOTA, PUBG, Fortnite, every one those games have voice chat. So to compare cons and pros. Dont want to be mean or anything but everyones only arguement whos against it, is that it would raise toxicity and could be annoying, and all of us know it can be negated by simply just muting them or leaving specific room(depends on system). And there are pros that cant be argued about...I just dont see how could it be more useless or dmging to game than actually prospering