As has been mentioned dozens of times in the thread already, the IRC protocol would not need to be changed one bit. The actual chats take place via DCC, not IRC. Whether mIRC supports it or not, video and audio chat is already taking place over DCC and has been for quite some time. For the users of those clients which do support it I don't think you'd find many/any who'd say it's "ruined" IRC - clearly it hasn't affected you that much, you don't seem to realise it's already available to many people.
