You can go straight there, but you miss some important lines. On the beta I was unable to complete the zone with Ysera to go to the southern hub because I didn't do the main line from the breadcrumb quest. I had to go get it and come back to her.
This, however, may be different from when I did the quests on beta. The breadcrumb quest did not exist when I started Hyjal, but was implemented halfway through my questing there which could account for my suddenly not being able to do the last quest with Ysera after waking up the final Ancient.