Okay, I'll give it a try:
Bad:
~ Noobs spamming nonstop in your ear, making you want to overdose on Advil.
~ little 8 year old kids trying to be "cool" and cussing everyone out.
~ teenagers discussing nasty and inappropriate material.
~"LLAAAGGGG!!!!" goes right into your ear, and probably it would be like 8 people screaming at the same time.
~ Need I say more?
Good:
~Useful in TDMs for discussing strategy and giving orders to teammates, no one ever hardly chats in a TDM because they're getting shot at!
~ You don't stop whatever you're doing to constantly type messages to your chatty friends.
All in all, I voted "no" for this. Don't get me wrong, it's an interesting idea, but it just couldn't happen. Poor Badspot would have a lot of complaints about chatty noobs and all these other problems that arise from the voice chat.