Looks they are indeed adding shout channels at some point (according to a thread in the UI section).

Not sure what you guys are talking about the wards being overcrowded if they were linked. At least on my server, if you go to the wards in LL or Gridania you'll see maybe 2 or 3 retainers in each area of the wards. They would be equally crowded as Ul'dah is, but accessible everywhere.