So after the event today a few of us took on Arah's story mode.It was a terrible experience. It felt like half the time was spent shooting turrets with trash mobs slapping us occasionally, and the battle with Zhaitan was just shooting at him with turrets for far too long while he humped a building. I cannot see the Elder Dragons as anything approaching a serious threat when fighting one took less thought and effort than most personal story missions.
Also, Zhaitan is way smaller than the concept art in the loading screen implies.
EDIT:I have to do all of this again to finish the personal story? Ugh....
Sadly yea, if you weren't at that point in your storyline...then you'll need to redo it. I agree though that it was a HUGE let down/horrible mechanics.