The official Echo Isles page indicates that there's plenty more going on to trouble the Darkspear than Zalazane, outright stating that Horde leadership will undergo a schism, and that Vol'Jin has potentially dangerous information about the political struggles that both the Darkspear and the Horde at large are undergoing.
One confusing bit of information in there, though -- this is on the official Cataclysm site and listed as a Cataclysm feature, but it was formerly announced as pre-Cataclysm content for Patch 3.3.9. Is it possible the new experience has been pushed back, or is this just being pushed as a Cataclysm feature to draw in new trolls?
Either way, Cataclysm should be a pretty exciting time for the Darkspear -- you get your island back and you get to turn into a bear.* What more could you ask for?
*certain class restrictions may apply
World of Warcraft: Cataclysm will destroy Azeroth as we know it. Nothing will be the same. In WoW.com's Guide to Cataclysm you can find out everything you need to know about WoW's third expansion. From Goblins and Worgens to Mastery and Guild changes, it's all there for your cataclysmic enjoyment.