While I wouldn't use the system, if it gets people off of the forums and into the game, then let's slap it on.

More than global chat though, I would love a global in game, and player made, message board. Just like a small one/two line banner across the top or bottom of the screen; showing the first sentence or so of random messages that players can create. You can click on the banner and filter through all the messages, from newest to oldest, and browse what people are saying. Would definitely need some limitations tho. Like one post per player at a time (and you can delete your post at anytime) and they get deleted when you log off, and why not even make em cost some money to make a post. And some kind of options to select who sees your message. So if your looking for some people for Limsa leves, just limit it so only people around Limsa could see and etc etc