I am throwing in my vote for in game chat. It makes me humanize other players when they decide to use it. And adds to immersion. If they don't want to talk, then just listen so I don't have to type.
I've never seen a good in-game voice chat. It's always been quite weak and low-quality. I'd rather use Skype and talk to people I know, and just type to people I'm meeting.
In RTCW you had voice commands. You hit V then two numbers to get a voice from your character. Such as V 1 1 Thank you. V 5 3 Incomming and so forth.
In this game you can hold E and bring up a radial dial of a couple basic command/announcements. Perhaps if we could edit the radial or even add a couple more of our choosing/customization it would work.
I don't like in game voice chat because I don't want to be grouped with some retard who mouths off or acts like a tool. With friends/guild I will use vent. For random pugs if the content is that hard that I need to talk to the people and organize, I would rather do it with people I know. So for me I would have it turned off all the time. For the times the content needed it I would only go with people I know and the people I know and will play with use vent.
Stranger danger! I don't know if it will be a highly used feature. WoW had one and no one used it, SC2 has one and no one uses it. Would be interesting to see how it plays out though.