Lots of explosives there. And one very carefull explosive master. No surprise, blowing up the Stormwind might be deadly, sowow gold needs carefull planning. The wall you see on picture will disappear later to make room (and path) for new harbour. Preparation for the Wrath of the Lich King (WotLK)! Wanna see it? Look close to cathedral, left side when facing it.

Worth mentions is - there is nothing on "other" side. It's still unfinished area, you still end "under" actual Stormwind and there are still two big holed leading outside of world. But it's certain, Blizz will have to do some tweaking to that place later :)