I've done a good amount of PvP in my day. I've read through hundreds of posts on this and other various forums complaining about PvP. I've come to the conclusion that the biggest problem is the ability for opponents to communicate.
I.e : "WHAT NO FAIR HE HEALED!! CHEATER!" "MINIONS ARE FOR CHEATS" ...and the list goes on and on, I'm sure you've heard of a ton.
If KI made it so that you could ONLY communicate with your own team, the majority of these 'grievers' would be silenced.
In addition, it would be easier to plan out strategy without the other team listening in.
I like this idea. It could be an option on the chat bar at the bottom where you click it and you're talking to your team mates and your team mates only.
I think an easy fix is that you auto-group with the folks you are PvPing with. That will allow you to talk in group chat and plan out your strategy accordingly. I also personally think that you should not be able to communicate with the other team at all, since anything said between the teams is usually unproductive.
Once the PvP battle is over, you will be released from the "group" and ready to join another battle, or go on your way.
Quantize... I love you. I completely agree. That would make me so darn happy. The only thing I would like to see is an option to see their chat. Since many times I duel against friends in the arena. Not all the time, but when I do I would like to be abke to chat with them.