Here’s some perspective on how large the Vashj’ir zone is. I have completed all the quests in the first sub-zone, Kelp Forest. I’ve previously written about my first impressions and how you get over there initially.
The zone, like Mt Hyjal, is storylined in the new way that quests unfold in Cataclysm. You have breadcrumb quests which lead you to the next quest hub, who may have been phased-out before. You only have a few quests in your log at any time. Sometimes you’ll get four at once.
The player experience is guided, much like an RPG standalone game. Lore-nerds will love it. You truly feel part of an epic and unfolding story. In Vashj’ir you move through the zone as a survivor of your boat being attacked by a giant squid, and then need to save and feed your fellow survivors. That’s all in the first quest hub which I’ve shown in a large circle on the Kelp Forest map shown.
You run quests to strengthen them, then find other survivors and get to uncover pieces of the puzzle about who are these Naga, who do they serve and why did this massive island suddenly appear off the coast of Stormwind? This leads to finding another survivor who’s floating above a clam’s air bubble, who you escort into a cave. That’s the next hub in the smuggler’s cove.
This process continues down to the south of the map, including Harrison Jones making his (awesome) appearance. He’s phased out initially, so you can’t skip to him. Same with the other quest hubs. This is the controlled and guided storytelling I’ve mentioned. You get two nice blues along the way.
Vashj’ir is huge. I’ve done Kelp Forest, and it took a while. Check it out compared to the whole zone. There are other hubs currently unavailable because of a bug with the cookie-crumb quest, which would unlock your epic swimming mount: a seahorse. However by swimming off with no direction I did find another hub in Shimmering Expanse which is working really well, some amazing quests there too.