The real concern about Voice Chat in League of Legends
Toxicity!
Nope. If it was just a worry about toxicity then the answer would be the same as it is for the text box, mute them and move on.
Teammates doing annoying things with their mic on!
Nope. While certainly annoying and something I am not looking forward to, that also would be fixed by muting people.
The real problem? Muting will cut off all communication between two players, making things worse than they are now.
Imagine if, with the current system, players had no cap on pings and muting a player muted their pings to. There'd be nothing to stop someone from "?" spamming you literally from the start of the match until the end other than you muting them, but as soon as you did you got absolutely no communication from that player. No signal that enemies are missing from some area beyond where you stand, no signal to group, no information about ultimate timers or summoner spells, no signals to attack Baron or Dragon. Nothing.
In such a scenario, muting your allies would make your team's coordination significantly worse. As such, if you want to win you wouldn't be able to mute someone who's irritating, or raging but still trying to win, because in doing so you'd lose the ability to coordinate in game.
That's what muting someone in Voice Chat would be like. You'd miss "Mid roaming bot" calls, or "Hang on, my ult's up in 5 seconds", because these calls would be moved to voice chat instead of pings.
Nonsense, people will still use pings!
Just like people still practice every role so they can play it in ranked, right? Only one year after the New Champion Select came out and people are already struggling to play other roles when they get Auto Filled.
Look at the pings in LCS matches and you'll notice something. A lot of them are the generic blue dot ping, with the context filled in by voice chat, because the blue dot is faster than the selector wheel. MIA pings are almost non-existent, replaced by spoken commands. Imagine having to try and follow those types of pings in your own game. It'd be close to playing without pings at all.
But that's the LCS!
You see the same thing with groups of friends in Normals. It takes people making a conscious effort to use pings when on voice chat. While you or I may use the full array of pings while on voice chat, not everyone will. Newer players who don't have pings committed to muscle memory won't bother, and chances are the people who's audio is annoying you to the point where you'd want to mute them aren't either. The one "win" condition is that the rager who wants to win might still use pings assuming people will mute him anyway, but at best that means he's in the same position as he currently is, and at worse he also doesn't use useful pings.
If you compare the ping usage now to the ping usage 1 year after voice chat goes live I guarantee you'll notice a drop in useful pings.
Other games do fine with voice chat, why wouldn't League?
Other games with voice chat tend to last 5-10 minutes, and communicating with teammates at all is pretty optional. Most of them are FPS games that rely more on individual skill than teamwork.
The closest experience I've had to what League would be like with voice chat is Natural Selection 2, which is a hybrid FPS and RTS. While the FPS part relies a lot on individual skill, there's information communicated back and forth between the commander (we need to take position X) and the foot soldiers (we need flamethrowers to push them out). Muting the commander, or the commander muting the foot soldiers, just doesn't work well, since the strategy part of the game gets cut off.
If you consider League to be a strategy game at it's heart, then muting teammate's voice chat, when voice chat is the new primary way to communicate, will similarly be problematic.
#TL;DR:
While Riot says they want to have Voice Chat be an opt-in experience where you can mute others, there won't be a realistic way to mute players if this goes live. Voice chat for League makes sense for groups that know each other and are OK with whatever comes over voice, but such groups typically have 3rd party solutions in place already anyways.
