I actually think it'll have the opposite effect. People tend to be more mean when it's anonymous, once you start talking it's more personal.
Like I said in the league forum thread, if you treat the player base like they'll always be toxic then it's going to be so. There's always going to be assholes, and leaving out a very fundamental feature that's in virtually every game because of them is bullshit.
Well like anyone else, I've had many of my games ruined by someone just deciding to stop playing and coordinating with the team because he had his feelings hurt or just outright thinks he's better than everyone. Stuff like that leaves a strong impression when it happens more than I dare say, 100 times. And though I'd really like to it's still hard for me to go into a ranked game with an attitude that isn't a tiny bit hostile because I'm preparing myself for that exact situation. But I try my best to stay calm, friendly and cooperative.
I wholeheartedly agree however that they should not be leaving the voice chat feature out just because of toxic players. I thought Riot sort of outlaws the toxic part anyway since they take a lot of measures to try and remove them from the community. And to be honest I think if it weren't for a lot of their efforts the community would've been in much worse shape right now. Though I do think they could've done a lot of things in a better way.
Also as for that video, yeah it certainly does. But I'd say that's still the best Yasuo execution I've seen by far.