In some other MMOs, there are public chat channels that people can talk in, no matter where they are on the server.
"Level 50" - You will automatically join this channel once you hit level 50. This channel is for level 50s. No matter where you are on the server, all level 50s can speak to each other. (This would be the most chatty out of all the channels.)
"Crafting" - This channel is for people who craft. You can manually join this channel and speak to other crafters on the server.
I realize that FF already has it's different chats, like /say /shout /guild, etc. However, those channels are very limited. The result of having limited chat is the game seeming like a ghost town, as many people in the past have complained.
I also realize that FFXIV is its own game and doesn't want to be like other MMOs, but having server-wide chats can make the game more...well...alive.