Universal region chat could become annoying, though. Einherjar, Dynamis, Abyssea, and Limbus at the least all share regions even when the zones themselves are completely separate. I don't want to hear someone's Dynamis-Jeuno shouts when I'm in Dynamis-Xarcabard.

City channels wouldn't be too bad, though. The server load increase isn't massive, and it allows people to hear and respond to shouts without standing in the central zone. Personally, I've always preferred Ru'Lude to Port Jeuno anyways.