I think if we can talk in game without any other program (skype, raidcall, ts etc.) it would be great.
Just think one moment, you are ganked and running for survive but if jungler come there you can beat both of them do you prefer to write "Jung come here" and to die when writing, or do you prefer just saying "Jungler come here we can beat them" and to not to die when speaking.
If you say "But then they'll abuse the voice chat and flame us" it's easy just put a "voice mute" and problem solved.
And then if you "But rito won't waste their time to listen voice records in tribunal" meh, they must do that ^^