Think it's a bad idea? Could be an option you can toggle on/off. I dare say it will help immersion to have comic style chat bubbles when players chat in local /say. I don't like the chat window to be honest. Everything is muddled down in the corner I hardly pay any attention to it.
Example : http://i.imgur.com/LOK90am.jpg
Maybe someone can make an add-on mod for it.